Adhesive composition, process for producing the same, adhesive film using the same, substrate for mounting semiconductor and semiconductor device

ABSTRACT

The present invention provides an adhesive composition which comprises (a) an epoxy resin, (b) a curing agent and (c) a polymer compound incompatible with said epoxy resin, and further optionally comprises (d) a filler and/or (e) a curing accelerator;
         a process for producing an adhesive composition, comprising: mixing (a) the epoxy resin and (b) the curing agent with (d) the fillers followed by mixing the resultant mixture with (c) the polymer compound incompatible with the epoxy resin;   an adhesive film comprising the above-mentioned adhesive composition formed into a film;   a substrate for mounting semiconductor comprising a wiring board and the above-mentioned adhesive film disposed thereon on its side where chips are to be mounted; and   a semiconductor device which comprises the above-mentioned adhesive film or the substrate for mounting semiconductor.

This application is a Continuation application of application Ser. No.11/476,725, filed Jun. 29, 2006, which is a Continuation application ofapplication Ser. No. 10/203,790, filed Aug. 14, 2002, the contents ofwhich are incorporated herein by reference in their entirety. No.10/203,790 is a National Stage application filed under 35 USC 371 ofInternational (PCT) Application No. PCT/JP01/01065, filed Feb. 15, 2001.

TECHNICAL FIELD

The present invention relates to an adhesive composition and a processfor producing the same, an adhesive film using the adhesive composition,a substrate for mounting semiconductor and a semiconductor device. Morespecifically, it relates to an adhesive composition which can form anadhesive film that has enough heat resistance and moisture resistancerequired for mounting semiconductor elements having a large coefficientof thermal expansion on a substrate for mounting semiconductor, and cansuppress an amount of volatilization at the time of use, a process forproducing the same, an adhesive film using the adhesive composition, asubstrate for mounting semiconductor, and a semiconductor device.

BACKGROUND ART

In recent years, the mounting density of electronic parts has beenincreased in accordance with the progress of electronic apparatuses, andnew type of mounting methods, e.g., a method of mounting a semiconductorpackage having almost the same size to the size of a semiconductor chip,or mounting a bare chip, called chip scale package or chip size package(hereinafter, simply referred to as “CSP”), are being employed.

One of the most important characteristics for a mounted board havingmounted thereon various electronic parts including a semiconductorelement is reliability. In the reliability, interconnection reliabilityagainst thermal fatigue is directly responsible for the reliability ofan apparatus using the mounted board and is therefore a very importantissue.

One of the causes of lowering the interconnection reliability is athermal stress due to the use of various materials having differentcoefficients of thermal expansion. Since the semiconductor element has acoefficient of thermal expansion as small as about 4 ppm/° C., whereasthe wiring board on which electronic parts are mounted has a coefficientof thermal expansion as high as 15 ppm/° C. or more, a thermal strain iscaused upon a thermal impact, which in turn generates a thermal stress.

A substrate having mounted thereon a semiconductor package having aconventional lead frame such as QFP and SOP, has kept reliability byabsorbing a thermal stress at a portion of the lead frame.

However, in the bare chip mounting, a method of connecting an electrodeof the semiconductor chip to a wiring board pad of the wiring boardusing a solder ball or a method of connecting by preparing a smallprojection called bump and using a conductive paste is employed.Therefore, a thermal stress is concentrated on this connecting portionthereby lowering the interconnection reliability. It has been known thatintroduction of a resin called underfill between the semiconductorelement and the wiring board is effective for dispersing the thermalstress. However, the number of steps for mounting is increased,elevating the cost. On the other hand, there is a method of connectingan electrode of the semiconductor element to a wiring pad of the wiringboard using conventional wire bonding, however, in this method, theboard must be coated with a resin for encapsulation for protecting thewire, thus increasing the number of steps for mounting.

CSP can be mounted together with other electronic parts, and ones havingvarious structures have been proposed as shown in Table 1 appearing atpage 5 of “Future of CSP (fine pitch BGA) put into practical use”, thearticle of Surface Mounting Technology, March, 1997, published by NikkanKogyo Shimbun Ltd. Especially a method using a tape and a carriersubstrate in a wiring board called interposer is being put intopractical use. This includes systems shown in the above table thatTessera, Inc. and Texas Instruments Inc. are developing. In thesesystems, a semiconductor device is mounted through a wiring board calledinterposer, and hence excellent interconnection reliability is exhibitedas reported in Shingaku Technical Report CPM96-121, ICD96-160 (1996-12)“Development of Tape BGA size CSP”, and Sharp Technical Journal, No. 66(1996-12) “Development of Chip Size Package”.

Between the semiconductor element of CSP and the wiring board calledinterposer, an adhesive film is preferably used which lowers the thermalstress caused by the difference in coefficient of thermal expansionbetween the semiconductor device and the wiring board. In addition, theadhesive film is also required to have moisture resistance and enduranceat high temperatures. Further, from the viewpoint of facilitatingcontrol of the production process, the adhesive film is desired to be ofa film type.

An adhesive of a film type is used in flexible printed circuit boards,and those comprised mainly of an acrylonitrile-butadiene rubber arefrequently used.

As printed circuit board materials for improving a moisture resistance,Japanese Provisional Patent Publication No. 243180/1985 discloses anadhesive comprising an acrylic resin, an epoxy resin, polyisocyanate,and an inorganic filler, and Japanese Provisional Patent Publication No.138680/1986 discloses an adhesive comprising an acrylic resin, an epoxyresin, a compound having a urethane bond in the molecule and havingprimary amine at both terminals thereof and an inorganic filler.

A number of adhesives of a film type comprised mainly of anacrylonitrile-butadiene rubber are used. However, the adhesives havedisadvantages in that the adhesive force is significantly lowered aftertreated at high temperatures for a long time and that a resistance toelectrolytic corrosion is poor. The adhesives suffer markeddeterioration especially in the moisture resistance test under severeconditions in, e.g., a pressure cooker test (PCT) treatment, which isused for the reliability evaluation of semiconductor relating parts.

The adhesive disclosed in each of Japanese Provisional PatentPublications No. 243180/1985 and No. 138680/1986 suffers markeddeterioration when subjected to moisture resistance test under severeconditions in a PCT treatment.

The above adhesive cannot be used as a printed circuit board relatingmaterial in the mounting process of a semiconductor element on a wiringboard, because the difference in coefficient of thermal expansionbetween the semiconductor element and the wiring board called interposeris large, thereby generating a crack during reflow. In addition, theadhesive cannot be used, since it suffers marked deterioration whensubjected to moisture resistance test under severe conditions in thetemperature cycle test or PCT treatment.

The present inventors have found that, as described in JapaneseProvisional Patent Publication No. 2000-154361, by reducing the elasticmodulus of the adhesive film around room temperature, the thermal stresscaused in the heating-cooling cycle due to the difference in coefficientof thermal expansion between the semiconductor chip and the wiring boardcan be lowered, so that no crack is caused during reflow and no damageis observed after temperature cycle test, thus giving the adhesive filmexcellent in heat resistance.

However, when demands on heat resistance and resistance to reflow crackbecome severer in future, it is necessary that higher level of heatresistance and moisture resistance be imparted to the adhesive film byincreasing the peel strength at high temperatures and elastic modulus athigh temperatures. Further, it is necessary to make an amount ofvolatilization from the adhesive a less level. When the amount ofvolatilization is at a certain level or higher, peripheral apparatusesare possibly contaminated during the process of operation.

An object of the present invention is to provide an adhesive compositionwhich can form an adhesive film that has enough heat resistance andmoisture resistance required for mounting semiconductor elements havinga large coefficient of thermal expansion on a substrate for mountingsemiconductor, and that can suppress an amount of volatilization at thetime of use, a process for producing the same, an adhesive film usingthe adhesive composition, a substrate for mounting semiconductor, and asemiconductor device.

DISCLOSURE OF THE INVENTION

The adhesive composition of the present invention is characterized inthat it comprises (a) an epoxy resin, (b) a curing agent, and (c) apolymer compound incompatible with the epoxy resin, and furthercomprises (d) a filler and/or (e) a curing accelerator, as necessary.

In addition, the adhesive composition of the present invention ischaracterized in that it is separated into two phases after being curedas viewed in the cross-section thereof.

Further, the adhesive composition of the present invention ischaracterized in that it gives a cured product having a storage elasticmodulus at 240° C. of 1 to 20 MPa.

Further, the adhesive composition of the present invention ischaracterized in that it has pores having an average diameter of 0.01 μmto 2 μm after being cured, wherein the volume percentage of the pores inthe composition cured is 0.1 to 20% by volume.

The process for producing an adhesive composition of the presentinvention is characterized in that it comprises mixing (a) an epoxyresin with (b) a curing agent and (d) a filler, and then, mixing theresultant mixture with (c) a polymer compound incompatible with theepoxy resin.

The adhesive film of the present invention is characterized in that itis obtained by forming the above adhesive composition into a film.

The adhesive film of the present invention is characterized in that itcomprises a laminated cured product of an adhesive composition and apolyimide film, wherein, when the laminated cured product is subjectedto moisture absorption treatment followed by heat treatment at 260° C.for 120 seconds, the resultant laminated cured product does not sufferpeeling with a diameter of 2 mm or more.

In addition, the adhesive film of the present invention is characterizedin that it has pores having an average diameter of 0.01 μm to 2 μm afterbeing cured, wherein the volume percentage of the pores in the adhesivefilm is 0.1 to 20% by volume.

Further, the adhesive film of the present invention is characterized inthat it is separated into two phases after being cured as viewed in thecross-section thereof.

Further, the adhesive film of the present invention is characterized inthat it exhibits lowering in flow amount after 72 hours at 60° C. of 50%or less.

The adhesive film having a support of the present invention ischaracterized in that it comprises the above adhesive film(s) laminateddirectly or mediated by another layer, on one surface or both surfacesof the support layer.

Further, the adhesive film having a support of the present invention ischaracterized in that it further comprises, on one surface or bothsurfaces thereof, a layer or layers for protecting the adhesive layer.

The substrate for mounting semiconductor of the present invention ischaracterized in that it comprises a wiring board and the above adhesivefilm disposed on a chip-mounting surface thereof.

The semiconductor device of the present invention is characterized inthat it uses the above adhesive film or substrate for mountingsemiconductor.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a view showing a semiconductor device of the presentinvention. In the drawing, reference numeral 1 denotes a semiconductorchip, 2 denotes an adhesive film, 3 denotes a wiring board, 4 denotes anencapsulating material 5 denotes a beam lead, and 6 denotes a solderball.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinbelow, the present invention will be described in more detail.

(a) The epoxy resin to be used in the present invention is notparticularly limited as long as it is cured to exhibit an adhesiveaction. An epoxy resin having two or more functional groups andpreferably having a molecular weight of less than 5,000, more preferablyless than 3,000 can be used. For example, bifunctional epoxy resins suchas a bisphenol A type epoxy resin and a bisphenol F type epoxy resin,and novolak epoxy resins such as a phenolic novolak type epoxy resin anda cresol novolak type epoxy resin, can be used. In addition, generallyknown polyfunctional epoxy resins and heterocycle-containing epoxyresins can be used.

As these epoxy resins which are commercially available, for example,bisphenol A type epoxy resins such as EPIKOTE 807, EPIKOTE 815, EPIKOTE825, EPIKOTE 827, EPIKOTE 828, EPIKOTE 834, EPIKOTE 1001, EPIKOTE 1002,EPIKOTE 1003, EPIKOTE 1055, EPIKOTE 1004, EPIKOTE 1004AF, EPIKOTE 1007,EPIKOTE 1009, EPIKOTE 1003F and EPIKOTE 1004F (manufactured by JapanEpoxy Resins Co., Ltd., trade name), DER-330, DER-301, DER-361, DER-661,DER-662, DER-663D, DER-664, DER-664U, DER-667, DER-642U, DER-672U,DER-673MF, DER-668 and DER-669 (they are manufactured by Dow ChemicalCompany, trade name), YD8125 and YDF8170 (manufactured by Tohto KaseiCo., Ltd., trade name); bisphenol F type epoxy resins such as YDF-2004(manufactured by Tohto Kasei Co., Ltd., trade name); phenolic novolaktype epoxy resins such as EPIKOTE 152 and EPIKOTE 154 (manufactured byJapan Epoxy Resins Co., Ltd., trade name), EPPN-201 (manufactured byNippon Kayaku Co., Ltd., trade name) and DEN-438 (manufactured by DowChemical Company, trade name); cresol novolak type epoxy resins such asEPIKOTE 180S65 (manufactured by Japan Epoxy Resins Co., Ltd., tradename), Araldite ECN1273, Araldite ECN1280 and Araldite ECN1299(manufactured by Ciba Specialty Chemicals Inc., trade name), YDCN-701,YDCN-702, YDCN-703 and YDCN-704 (manufactured by Tohto Kasei Co., Ltd.,trade name), EOCN-102S, EOCN-103S, EOCN-104S, EOCN-1012, EOCN-1020,EOCN-1025 and EOCN-1027 (manufactured by Nippon Kayaku Co., Ltd., tradename), ESCN-195×, ESCN-200L and ESCN-220 (manufactured by SumitomoChemical CO., Ltd., trade name); polyfunctional epoxy resins such asEPON 1031S, EPIKOTE 1032H60 and EPIKOTE 157S70 (manufactured by JapanEpoxy Resins Co., Ltd., trade name), Araldite 0163 (manufactured by CibaSpecialty Chemicals Inc., trade name), Denacol EX-611, Denacol EX-614,Denacol EX-614B, Denacol EX-622, Denacol EX-512, Denacol EX-521, DenacolEX-421, Denacol EX-411 and Denacol EX-321 (manufactured by NagaseChemicals Ltd., trade name), EPPN501H and EPPN502H (manufactured byNippon Kayaku Co., Ltd., trade name); amine type epoxy resins such asEPIKOTE 604 (manufactured by Japan Epoxy Resins Co., Ltd., trade name),YH-434 (manufactured by Tohto Kasei Co., Ltd., trade name), TETRAD-X andTETRAD-C (manufactured by Mitsubishi Gas Chemical Company, Inc., tradename) and ELM-120 (manufactured by Sumitomo Chemical Co., Ltd., tradename); heterocycle-containing epoxy resins such as Araldite PT810(manufactured by Ciba Specialty Chemicals Inc., trade name); andalicyclic epoxy resins such as ERL4234, ERL4299, ERL4221 and ERL4206(manufactured by Union Carbide Corporation, trade name) can be used, andone kind or two or more kinds of them can be also used in combination.

In the present invention, in terms of heat resistance, an epoxy resinbeing in a solid state at room temperature and having a softening pointof 50° C. or more as measured by a ring and ball method is preferablyused in an amount of 20% by weight or more, more preferably 40% byweight or more, further preferably 60% by weight or more, based on thetotal weight of the epoxy resins used. Examples of such epoxy resinsinclude a bisphenol A type epoxy resin, a bisphenol F type epoxy resin,a bisphenol S type epoxy resin, an alicyclic type epoxy resin, analiphatic linear epoxy resin, a phenolic novolak type epoxy resin, acresol novolak type epoxy resin, a bisphenol A novolak type epoxy resin,diglycidyl ether compounds of a biphenol, diglycidyl ether compounds ofa naphthalenediol, diglycidyl ether compounds of a phenol, diglycidylether compounds of an alcohol, and alkyl-substituted compounds, halides,and hydrogenation products thereof. These may be used in combination,and may contain an ingredient other than the epoxy resins as animpurity.

It is preferred to use an epoxy resin having a large molecular weightand having a softening point of 50° C. or more and a rubber incombination wherein the difference in polarity between the epoxy resinand the rubber is large since these are difficultly compatible to eachother.

It is necessary that the epoxy resin be incompatible with the polymercompound, however, when two or more epoxy resins are used in combinationas the epoxy resin, if the mixture of the epoxy resins is incompatiblewith the polymer compound, each of the epoxy resins is not necessarilyincompatible with the polymer compound. For example, when epoxy resinYDCN703, which is solely incompatible with the polymer compound andwhich has a softening point of 50° C. or more, and epoxy resin EPIKOTE828, which is compatible by itself with the polymer compound and whichhas a softening point of less than 50° C., are used in combination, amixture of these epoxy resins in a weight ratio of 1:0 to 1:10 isincompatible with the polymer compound.

(b) The curing agent to be used in the present invention is notparticularly limited as long as it can cure an epoxy resin. Examples ofsuch curing agents include polyfunctional phenols, amines, imidazolecompounds, acid anhydrides, organophosphorus compounds, and halidesthereof, polyamide, polysulfide, and boron trifluoride.

Examples of polyfunctional phenols include monocyclic bifunctionalphenols such as hydroquinone, resorcinol, and catechol; polycyclicbifunctional phenols such as bisphenol A, bisphenol F, bisphenol S, anaphthalenediol, and a biphenol; and halides and alkyl-substitutedcompounds thereof. Further, examples include phenolic resins which arepolycondensation products of the above phenols and aldehydes such as aphenolic novolak resin, a resol resin, a bisphenol A novolak resin, anda cresol novolak resin.

Examples of preferable phenolic resin curing agents that arecommercially available include, for example, PHENOLITE LF2882, PHENOLITELY2822, PHENOLITE TD-2090, PHENOLITE TD-2149, PHENOLITE VH4150, andPHENOLITE VH4170, (manufactured by Dainippon Ink & Chemicals, Inc.,trade names).

In the present invention, it is preferred to use a phenolic resin havinga hydroxyl equivalent of 150 g/eq or more. The above phenolic resin isnot particularly limited as long as it has the above-mentioned hydroxylequivalent value, and novolak type or resol type resins are preferablyused because they have excellent electrolytic corrosion resistance whenabsorbing moisture.

As specific examples of phenolic resins mentioned above, there can bementioned, for example, phenolic resins represented by the followinggeneral formula (I):

-   -   wherein R¹ each may be the same or different from each other and        represents a hydrogen atom, a straight or branched alkyl group        having 1 to 10 carbon atoms, a cyclic alkyl group, an aralkyl        group, an alkenyl group, a hydroxyl group, an aryl group or a        halogen atom; n represents an integer of 1 to 3; and m        represents an integer of 0 to 50.        The phenolic resin is not particularly limited as long as it        corresponds to formula (I), and, from the viewpoint of obtaining        excellent moisture resistance, it is preferred that the phenolic        resin exhibits a water absorption of 2% by weight or less after        being placed in a thermo-humidistatic chamber at 85° C. at a        relative humidity (RH) of 85% for 48 hours, Further, it is        preferred to use a phenolic resin which exhibits a weight loss        by heating at 350° C. (temperature elevation rate: 5° C./min;        atmosphere: nitrogen gas) of less than 5% by weight as measured        by a thermogravimetric analyzer (TGA) because an amount of the        volatilized components is suppressed during heating and        processing, thereby improving the reliability of various        properties such as a heat resistance and a moisture resistance,        and contamination of the peripheral apparatuses due to the        volatile components during operations including heating and        processing can be reduced.

The phenolic resin represented by formula (I) in the present inventioncan be obtained by, for example, reacting a phenolic compound with axylylene compound comprised of divalent linking groups in the absence orpresence of an acid catalyst.

Examples of the above-mentioned phenolic resins include, for example,Milex XLC-series and Milex XL series (manufactured by Mitsui Chemicals,Inc., trade names).

As formulation amounts when the above-mentioned phenolic resin and theepoxy resin are used in combination, the equivalents ratio of the epoxyequivalent to the hydroxyl equivalent is preferably 0.70:0.30 to0.30:0.70, more preferably 0.65:0.35 to 0.35:0.65, further preferably0.60:0.30 to 0.30:0.60, especially preferably 0.55:0.45 to 0.45:0.55.When the ratio falls outside of the above range, the resultant adhesivepossibly has poor curing properties.

The phenolic compounds used for production of the phenolic resin of theformula (I) can be exemplified by phenol, o-cresol, m-cresol, p-cresol,o-ethylphenol, p-ethylphenol, o-n-propylphenol, m-n-propylphenol,p-n-propylphenol, o-isopropylphenol, m-isopropylphenol,p-isopropylphenol, o-n-butylphenol, m-n-butylphenol, p-n-butylphenol,o-isobutylphenol, m-isobutylphenol, p-isobutylphenol, octylphenol,nonylphenol, 2,4-xylenol, 2,6-xylenol, 3,5-xylenol,2,4,6-trimethylphenol, resorcin, catechol, hydroquinone,4-methoxyphenol, o-phenylphenol, m-phenylphenol, p-phenylphenol,p-cyclohexylphenol, o-allylphenol, p-allylphenol, o-benzylphenol,p-benzylphenol, o-chlorophenol, p-chlorophenol, o-bromophenol,p-bromophenol, o-iodophenol, p-iodophenol, o-fluorophenol,m-fluorophenol, p-fluorophenol, etc. These phenolic compounds may beused singly or by mixing two or more kinds thereof. Phenol, o-cresol,m-cresol, p-cresol, etc. are particularly preferred.

As the xylylene compound which is a divalent linking group to be usedfor production of the phenolic resin of the formula (I), the followingxylylene dihalides, xylylene glycols and their derivatives can be used.That is, there may be mentioned α,α′-dichloro-p-xylene,α,α′-dichloro-m-xylene, α,α′-dichloro-o-xylene, α,α′-dibromo-p-xylene,α,α′-dibromo-m-xylene, α,α′-dibromo-o-xylene, α,α′-diiodo-p-xylene,α,α′-diiodo-m-xylene, α,α′-diiodo-o-xylene, α,α′-dihydroxy-p-xylene,α,α′-dihydroxy-m-xylene, α,α′-dihydroxy-o-xylene,α,α′-dimethoxy-p-xylene, α,α′-dimethoxy-m-xylene,α,α′-dimethoxy-o-xylene, α,α′-diethoxy-p-xylene, α,α′-diethoxy-m-xylene,α,α′-diethoxy-o-xylene, α,α′-di-n-propoxy-p-xylene,α,α′-n-propoxy-m-xylene, α,α′-di-n-propoxy-o-xylene,α,α′-di-isopropoxy-p-xylene, α,α′-diisopropoxy-m-xylene,α,α′-diisopropoxy-o-xylene, α,α′-di-n-butoxy-p-xylene,α,α′-di-n-butoxy-m-xylene, α,α′-di-n-butoxy-o-xylene,α,α′-diisobutoxy-p-xylene, α,α′-diisobutoxy-m-xylene,α,α′-diisobutoxy-o-xylene, α,α′-di-tert-butoxy-p-xylene,α,α′-di-tert-butoxy-m-xylene and α,α′-di-tert-butoxy-o-xylene. Thesecompounds can be used singly or two or more kinds thereof can be used asa mixture. Of these, particularly preferred are α,α′-dichloro-p-xylene,α,α′-dichloro-m-xylene, α,α′-dichloro-o-xylene, α,α′-dihydroxy-p-xylene,α,α′-dihydroxy-m-xylene, α,α′-dihydroxy-o-xylene,α,α′-dimethoxy-p-xylene, α,α′-dimethoxy-m-xylene andα,α′-dimethoxy-o-xylene.

When the above-mentioned phenolic compound and the xylylene compound areto be reacted, the reaction is carried out by using an acid catalyst,e.g., a mineral acid such as hydrochloric acid, sulfuric acid,phosphoric acid, polyphosphoric acid, etc.; an organic carboxylic acidsuch as dimethyl sulfate, diethyl sulfate, p-toluenesulfonic acid,methanesulfonic acid, ethanesulfonic acid, etc.; a superstrong acid suchas trifluoromethanesulfonic acid, etc.; a strong acid ion-exchange resinsuch as an alkanesulfonic acid ion-exchange resin; a superstrong acidion-exchange resins such as a perfluoroalkanesulfonic acid ion-exchangeresin (trade name: Nation; manufactured by Du Pont Company); natural orsynthetic zeolite; or activated clay (acid clay), etc. so that thexylylene compound as a raw material substantially disappears at 50 to250° C. and the composition of the reaction product becomes constant.The reaction time varies depending on the raw material and the reactiontemperature, and it is generally about 1 to 15 hours, and may beactually determined while tracing the composition of the reactionproduct by GPC (gel permeation chromatography), etc. When ahalogenoxylene derivative such as α,α′-dichloro-p-xylene isexceptionally used, the reaction proceeds in the absence of a catalystwhile generating the corresponding hydrogen halide gas. Therefore, insuch a case, no acid catalyst is needed. In other cases, the reactionproceeds in the presence of an acid catalyst to generate water oralcohol, correspondingly. With respect to the molar ratio of thephenolic compound and the xylylene compound in the reaction, generally,the phenolic compound is used in an excess amount, and, after completionof the reaction, the unreacted phenolic compound is recovered. In thiscase, the average molecular weight of the phenolic resin depends on theamount of the phenolic compound used, and the larger the amount of thephenolic compound, the lower the average molecular weight of thephenolic resin obtained. A phenolic resin with the phenolic compoundportion being an allylphenol can be obtained by, for example, a methodin which a phenolic resin which is not allylated is prepared, and then,allylation is carried out by reacting it with an allyl halide to form anallyl ether, followed by Claisen conversion.

Examples of amines include aliphatic or aromatic primary amines,secondary amines, tertiary amines, quaternary ammonium salts, alicyclicamines, guanidines, urea derivatives, etc.

As an example of these compounds, there may be mentioned byN,N-benzyldimethylamine, 2-(dimethylaminomethyl)phenol,2,4,6-tris(dimethylaminomethyl)phenol, tetramethylguanidine,triethanolamine, N,N′-dimethylpiperidine, 1,4-diazabicyclo[2.2.2]octane,1,8-diazabicyclo[5.4.0]-7-undecene, 1,5-diazabicyclo[4.4.0]-5-nonene,hexamethylenetetramine, pyridine, picoline, piperidine, pyrrolidine,dimethylcyclohexylamine, dimethylhexylamine, cyclohexylamine,diisobutylamine, di-n-butylamine, diphenylamine, N-methylaniline,tri-n-propylamine, tri-n-octylamine, tri-n-butylamine, triphenylamine,tetramethylammonium chloride, tetramethylammonium bromide,tetramethylammonium iodide, triethylenetetramine,diaminodiphenylmethane, diaminodiphenyl ether, dicyandiamide,tolylbiguanide, guanylurea, dimethylurea, etc.

Examples of imidazole compound include imidazole, 2-ethylimidazole,2-ethyl-4-methylimidazole, 2-methylimidazole, 2-phenylimidazole,2-undecylimidazole, 1-benzyl-2-methylimidazole, 2-heptadecylimidazole,4,5-diphenylimidazole, 2-methylimidazoline, 2-phenylimidazoline,2-undecylimidazoline, 2-heptadecylimidazoline, 2-isopropylimidazole,2,4-dimethylimidazole, 2-phenyl-4-methylimidazole, 2-ethylimidazoline,2-phenyl-4-methylimidazoline, benzimidazole, 1-cyanoethylimidazole, etc.

Examples of anhydrides include phthalic anhydride, hexahydrophthalicanhydride, pyromellitic dianhydride, benzophenonetetracarboxylicdianhydride, etc.

As the organophosphorus compound, there is no particular limitation aslong as it is a phosphorus compound having an organic group, andexamples include hexamethylphosphoric triamide, tri(dichloropropyl)phosphate, tri(chloropropyl) phosphate, triphenyl phosphite, trimethylphosphate, phenylphosphonic acid, triphenylphosphine,tri-n-butylphosphine, diphenylphosphine, etc.

These curing agents can be used independently or in combination.

The formulation amount of these curing agents is not particularlylimited as long as the curing agent can proceed the curing reaction ofthe epoxy group, but the curing agent is preferably used in an amount of0.01 to 5.0 equivalents, especially preferably 0.8 to 1.2 equivalent,based on 1 mol of the epoxy group.

As the epoxy resin and the curing agent, it is preferred to use acompound having no mutagen, for example, a compound using no bisphenolA, since it has less influence on the environment and human bodies.

(c) The polymer compound incompatible with the epoxy resin used in thepresent invention is not particularly limited as long as it isincompatible with the epoxy resin, and examples include rubbers such asan acrylic copolymer, an acrylic rubber, etc., silicone resins, siliconemodified resins such as silicone modified polyamideimide, etc. To beincompatible with the epoxy resin indicates a property of beingseparated from the epoxy resin into two or more phases, Thecompatibility of the resins is defined as a visible light (600 nm)transmittance of a film (50 μm) prepared from a varnish containing theepoxy resin and the acrylic copolymer (component ratio=1:1). When thetransmittance of the film is 50% or more, the polymer compound is“compatible” with the epoxy resin, whereas, when the transmittance isless than 50%, the polymer compound is “incompatible (is notcompatible)” with the epoxy resin. As the polymer compound of thepresent invention, those having the transmittance of less than 30% arefurther preferred.

As (c) the polymer compound of the present invention, those having areactive group (functional group) and having a weight average molecularweight of 100,000 or more are preferred. Examples of the reactive groupsin the present invention include a carboxylic acid group, an aminogroup, a hydroxyl group, an epoxy group, etc. Especially when themonomer having a functional group used in the polymer compound isacrylic acid of a carboxylic acid type, the crosslinking reaction islikely to proceed, so that the adhesive force of the resultant adhesivemay be lowered due to gelation in a varnish state or an increase in thedegree of cure in a B-stage. Therefore, it is more preferred to useglycidyl acrylate or glycidyl methacrylate having an epoxy group whichdoes not cause the above phenomenon or causes the above phenomenontaking a longer period of time. As (c) the polymer compound in thepresent invention, it is further preferred to use an epoxygroup-containing acrylic copolymer having a weight average molecularweight of 100,000 or more. Component (c) in the present invention can beobtained by conducting a polymerization reaction so that unreactedmonomers remain in a polymer compound or by preparing a polymer compoundfollowed by addition of a reactive group-containing monomer thereto.

The weight average molecular weight is a polystyrene conversion valueobtained by a gel permeation chromatography (GPC) method using acalibration curve obtained by standard polystyrene.

Examples of acrylic copolymers include, for example, acrylic rubberswhich are copolymers of an acrylate or a methacrylate and acrylonitrile.Further, from the viewpoint of obtaining excellent adhesiveness andexcellent heat resistance, especially preferred is an acrylic copolymercontaining 0.5 to 6% by weight of glycidyl acrylate or glycidylmethacrylate as a functional group and having a glass transitiontemperature (hereinafter, referred to simply as “Tg”) of −50° C. to 30°C., further preferably −10° C. to 30° C., and having a weight averagemolecular weight of 100,000 or more. As an acrylic copolymer containing0.5 to 6% by weight of glycidyl acrylate or glycidyl methacrylate andhaving Tg of −10° C. or more and having a weight average molecularweight of 100,000 or more, there can be mentioned, for example,HTR-860P-3 (manufactured by Teikoku Chemical Industries Co., Ltd., tradename). It is more preferred that the copolymerization ratio for theglycidyl acrylate or glycidyl methacrylate used as a functional groupmonomer is 2 to 6% by weight. For obtaining a higher adhesive force, thecopolymerization ratio is preferably 2% by weight or more, and, when itexceeds 6% by weight, gelation may occur. As the remaining portion, amixture of an alkyl acrylate or an alkyl methacrylate having an alkylgroup of 1 to 8 carbon atoms such as methyl acrylate or methylmethacrylate, and styrene or acrylonitrile can be used. Of these, ethyl(meth)acrylate and/or butyl (meth)acrylate is particularly preferred. Itis preferred that the mixing ratio is adjusted considering the Tg of thecopolymer. When Tg is less than −10° C., the tackiness of the adhesivelayer or adhesive film in a B-stage tends to increase, so that thehandling properties may be sometimes poor. The polymerization method isnot particularly limited, and examples may include a pearlpolymerization and a solution polymerization, and a copolymer isobtained by these methods.

The weight average molecular weight of the epoxy group-containingacrylic copolymer is preferably 300,000 to 3,000,000, more preferably500,000 to 2,000,000. When the weight average molecular weight is lessthan 300,000, strength and flexibility of the copolymer in a sheet stateor in a film state may be lowered and tackiness thereof may beincreased. On the other hand, when it exceeds 3,000,000, the flowabilityof the copolymer may be low and thus there is a possibility that thecircuit filling property for wiring may be lowered.

With respect to the addition amount of (c) the polymer compoundincompatible with the epoxy resin, from the viewpoint of reducing theelastic modulus and suppressing the flowability during shaping, it ispreferred that the ratio A/B is 0.24 to 1.0, where A represents thetotal weight of (a) the epoxy resin and (b) the curing agent and Brepresents the weight of (c) the polymer compound incompatible with theepoxy resin. When the formulation ratio for the polymer compound is lessthan 0.24, the handling properties at high temperatures tend to be poor.On the other hand, when it exceeds 1.0, the effects of reducing theelastic modulus and suppressing the flowability during shaping tend tobe poor.

To the adhesive composition of the present invention, if desired, (d) afiller and/or (e) a curing accelerator can be further added.

Examples of (d) the filler used in the present invention include aninorganic filler and organic filler. From the viewpoint of improvinghandling properties, improving thermal conductivity, adjusting the meltviscosity and imparting thixotropic properties, etc., it is preferred toadd an inorganic filler.

The inorganic filler is not particularly limited, and examples mayinclude aluminum hydroxide, magnesium hydroxide, calcium carbonate,magnesium carbonate, calcium silicate, magnesium silicate, calciumoxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminumborate whisker, boron nitride, crystalline silica, amorphous silica,etc. These can be used independently or in combination. From theviewpoint of improving the thermal conductivity, aluminum oxide,aluminum nitride, boron nitride, crystalline silica, amorphous silica,etc. are preferred. From the viewpoint of adjusting the melt viscosityand imparting thixotropic properties, aluminum hydroxide, magnesiumhydroxide, calcium carbonate, magnesium carbonate, calcium silicate,magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide,crystalline silica, amorphous silica, etc. are preferred.

Examples of the organic filler include various rubber fillers such asacrylonitrile-butadiene rubber fillers and silicone rubber fillers, etc.These have effects of improving the flexibility at low temperatures andreducing the elastic modulus.

It is more preferred that the filler used in the present invention has acontact angle with water of 100 degrees or less. When the contact anglewith water exceeds 100 degrees, the effect attained by addition of thefiller is likely to be lowered. The contact angle with water ispreferably 60 degrees or less, since the effect of improving a reflowresistance is especially high. It is preferred that the filler has anaverage particle diameter of 0.005 μm or more to 0.1 μm or less. Whenthe average particle diameter of the filler is less than 0.005 μm, thedispersion property and the flowability tend to be lowered, and, on theother hand, when the average particle diameter exceeds 0.1 μm, theeffect of improving the adhesiveness tends to be decreased.

The contact angle of the filler with water can be measured by thefollowing method. A filler is subjected to compression molding toprepare a plane plate, and a water drop is placed on the plate and theangle of the water drop with the plate is measured by means of a contactangle meter. This measurement is repeated 10 times to obtain an averagevalue, and this average value is used as a value of the contact angle.

Examples of such a filler include silica, alumina, antimony oxide andthe like. Silica is commercially available from C.I. KASEI CO., LTD. inthe trade name of NanoTek SiO₂ (contact angle: 43 degrees; averageparticle diameter: 0.012 μm) or available from Nippon Aerosil Co., Ltd.in the trade name of Aerosil R972 (average particle diameter: 0.016 μm).Alumina is commercially available from C. I. KASEI CO., LTD. in thetrade name of NanoTek Al₂O₃ (contact angle: 55 degrees; average particlediameter: 0.033 μm). Diantimony trioxide is commercially available fromNihon Mining & Concentrating Co., Ltd. in the trade name of PATOX-U(contact angle: 43 degrees; average particle diameter: 0.02 μm).

It is preferred that the amount of the filler added is 0 part by weightor more to 50 parts by weight or less based on 100 parts by weight ofthe total weight of the epoxy resin and the curing agent. When theamount of the filler used exceeds 50 parts by weight, problems may arisesuch that the storage elastic modulus increases and the adhesivenessbecomes poor. The amount of the filler used is further preferably 5parts by weight or more to less than 40 parts by weights especiallypreferably 10 parts by weight or more to less than 30 parts by weight.

(e) The curing accelerator to be used in the adhesive composition of thepresent invention is not particularly limited, and, for example,tertiary amines, imidazoles, quaternary ammonium salts, etc. can beused. Examples of imidazoles include 2-methylimidazole,2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole,1-cyanoethyl-2-phenylimidazolium trimellitate, etc., and these can beused independently or in combination. Imidazoles are commerciallyavailable from, for example, Shikoku Kasei Kogyo Co. in the trade namesof 2E4MZ, 2PZ-CN, and 2PZ-CNS.

From the viewpoint of prolonging the duration of use of the film, it ispreferred that the curing accelerator has potentiality. Representativeexamples thereof include dihydrazide compounds such as dicyandiamide,adipic dihydrazide, etc., guanamine acid, melamine acid, additionproducts of an epoxy compound and an imidazole compound, additionproducts of an epoxy compound and a dialkylamine, addition products ofan amine and thiourea, addition products of an amine and isocyanate,etc. From the viewpoint of reducing the activity at room temperature, itis preferred that the curing accelerator has an adduct structure.

The formulation amount of (e) the curing accelerator is preferably 0 to5.0% by weight, more preferably 0.05 to 3.0% by weight, furtherpreferably 0.2 to 3.0% by weight based on the total weight of the epoxyresin and the curing agent. When the formulation amount of the curingaccelerator exceeds 5.0% by weight, the storage stability of theresultant composition becomes poor, so that the pot life is likely to beinsufficient.

Also, in the present invention, it is preferred that the cured productof the adhesive composition has an elastic modulus in tensile of 1 to 20MPa as measured at 240° C. When the elastic modulus in tensile exceeds20 MPa, the stress relaxation property is lowered, increasing alikeliness to generate a bend. On the other hand, when the elasticmodulus in tensile is less than 1 MPa, a reflow crack is likely to becaused.

The measurement of an elastic modulus in tensile at 240° C. is conductedas follows. First, an adhesive composition having an initial length of20 mm (L) and having a thickness of about 50 μm is cured at 170° C. forone hour to prepare a cured film. The cured film is placed in athermostatic chamber at 240° C. in a state such that a predeterminedload of 1 to 10 kg (W) is applied to the cured film. After thetemperature of the cured film in the chamber reaches 240° C., anelongation (ΔL) and a cross-sectional area (S) of the cured film aredetermined to calculate an elastic modulus in tensile (E′) according tothe following formula:

E′=L·W/(ΔL·S)

The adhesive composition of the present invention preferably exhibits aweight loss by heating at 270° C. of 2% by weight or less, morepreferably 1.5% by weight, further preferably 1% by weight. When theweight loss by heating is more than the above value, the compositiontends to cause contamination of the peripheral apparatuses during theuse.

In the adhesive composition of the present invention, for improving theflexibility and the resistance to reflow crack, a high molecular-weightresin compatible with the epoxy resin can be added. The highmolecular-weight resin compatible with the epoxy resin is notparticularly limited, and, for example, phenoxy resins, highmolecular-weight epoxy resins, extra-high molecular-weight epoxy resins,large polarity functional group-containing rubbers, large polarityfunctional group-containing reactive rubbers, etc. can be used.

Phenoxy resins are commercially available from Tohto Kasei Co., Ltd. inthe trade names of Phenotot YP-40 and Phenotot YP-50, and also availablefrom Phenoxy Associates Co. in the trade names of PKHC, PKHH, and PKHJ.

Examples of high molecular-weight epoxy resins include highmolecular-weight epoxy resins having a molecular weight of 30,000 to80,000 and extra-high molecular-weight epoxy resins having a molecularweight exceeding 80,000 (see Japanese Patent Publications Nos.59617/1995, 59618/1995, 59619/1995, 59620/1995, 64911/1995, 68327/1995,etc.). As the large polarity functional group-containing reactiverubber, a carboxyl group-containing acrylonitrile-butadiene rubber iscommercially available from JSR Co. in the trade name of PNR-1.

It is preferred that the amount to be used of the high molecular-weightresin compatible with the epoxy resin is 40 parts by weight or lessbased on 100 parts by weight of the epoxy resin. When the amount exceeds40 parts by weight, the Tg of the epoxy resin layer is possibly lowered.

To the adhesive composition of the present invention, various kinds ofcoupling agents can be further added for improving bonding at theinterface between different kinds of materials. Examples of the couplingagents include silane type coupling agents, titanium type couplingagents, and aluminum type coupling agents, and the silane type couplingagents are most preferred.

The silane type coupling agent is not particularly restricted and theremay be mentioned, for example, vinyltrichlorosilane,vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane,vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane,γ-methacryloxypropylmethyldimethoxysilane,β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,γ-glycidoxypropyltrimethoxysilane,γ-glycidoxypropylmethyldimethoxysilane,γ-glycidoxypropylmethyldiethoxysilane,N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane,N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane,γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane,γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane,3-aminopropylmethyldiethoxysilane, 3-ureidopropyltriethoxysilane,3-ureidopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane,3-aminopropyl-tris(2-methoxy-ethoxy-ethoxy)silane,N-methyl-3-aminopropyltrimethoxysilane, triaminopropyl-trimethoxysilane,3-(4,5-dihydro)imidazol-1-yl-propyltrimethoxysilane,3-methacryloxypropyl-trimethoxysilane,3-mercaptopropylmethyldimethoxysilane,3-chloropropyl-methyldimethoxysilane, 3-chloropropyl-dimethoxysilane,3-cyanopropyl-triethoxysilane, hexamethyldisilazane,N,O-bis(trimethylsilyl)acetamide, methyltrimethoxysilane,methyltriethoxysilane, ethyltrichlorosilane, n-propyltrimethoxysilane,isobutyltrimethoxysilane, amyltrichlorosilane, octyltriethoxysilane,phenyltrimethoxysilane, phenyltriethoxysilane,methyltri(methacryloyloxyethoxy)silane, methyltri(glycidyloxy)silane,N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane,octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride,γ-chloropropylmethyldichlorosilane, γ-chloropropylmethyldimethoxysilane,γ-chloropropylmethyldiethoxysilane, trimethylsilyl isocyanate,dimethylsilyl isocyanate, methylsilyltriisocyanate, vinylsilyltriisocyanate, phenylsilyl triisocyanate, tetraisocyanate silane,ethoxysilane isocyanate, etc. These compounds can be used singly or incombination of two or more kinds thereof.

The titanium type coupling agent is not particularly limited and theremay be mentioned, for example, isopropyltrioctanoyl titanate,isopropyldimethacrylisostearoyl titanate,isopropyltridodecylbenzenesulfonyl titanate, isopropylisostearoyldiacryltitanate, isopropyltri(dioctylphosphate) titanate,isopropyltricumylphenyl titanate, isopropyltris(dioctylpyrophosphate)titanate, isopropyltris(n-aminoethyl) titanate,tetraisopropylbis(dioctylphosphite) titanate,tetraoctylbis(ditridecylphosphite) titanate,tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate,dicumylphenyloxyacetate titanate, bis(dioctylpyrophosphate)oxyacetatetitanate, tetraisopropyl titanate, tetranormalbutyl titanate, butyltitanate dimer, tetra(2-ethylhexyl) titanate, titanium acetylacetonate,polytitanium acetylacetonate, titanium octylene glycolate, titaniumlactate ammonium salt, titanium lactate, titanium lactate ethyl ester,polyhydroxytitanium stearate, tetramethyl orthotitanate, tetraethylorthotitanate, tetrapropyl orthotitanate, tetraisobutyl orthotitanate,stearyl titanate, cresyl titanate monomer, cresyl titanate polymer,diisopropoxy-bis(2,4-pentadionate) titanium (IV),diisopropyl-bis-triethanolamino titanate, octyleneglycol titanate,tetra-n-butoxy titanium polymer, tri-n-butoxytitanium monostearatepolymer, tri-n-butoxytitanium monostearate, etc. These compounds can beused singly or in combination of two or more kinds thereof.

The aluminum type coupling agent is not particularly limited and theremay be mentioned, for example, aluminum chelate compounds such asethylacetoacetate aluminum diisopropylate, aluminumtris(ethylacetoacetate), alkylacetoacetate aluminum diisopropylate,aluminum monoacetylacetatobis(ethylacetoacetate), aluminumtris(acetylacetonate), aluminum-monoisopropoxymonooleoxyethylacetoacetate, aluminum-di-n-butoxide-mono-ethylacetoacetate,aluminum-di-isopropoxide-mono-ethylacetoacetate, etc., and aluminumalcholates such as aluminum isopropylate, mono-sec-butoxyaluminumdiisopropylate, aluminum-sec-butyrate, aluminum ethylate, etc. Thesecompounds can be used singly or in combination of two or more kindsthereof.

In view of obtaining effects and heat resistance thereof as well asreducing the cost, it is preferred that an amount of the coupling agentto be added is 0 to 10 parts by weight based on 100 parts by weight ofthe total weight of the resins.

Further, to the adhesive composition of the present invention, foradsorbing an ionic impurity to improve the insulation reliability whenabsorbing moisture, an ion capturing agent can be added. The ioncapturing agent is not particularly limited, and a compound known as acopper damage preventing agent for preventing copper from ionizing anddissolving out, for example, a triazinethiol compound and a bisphenoltype reducing agent can be used, and inorganic ion adsorbents such aszirconium type and antimony bismuth type magnesium aluminum compoundscan be used.

In view of obtaining an effect aimed at by the addition and excellentheat resistance and reducing the cost, it is preferred that the amountof the ion capturing agent added is 0 to 10 parts by weight based on 100parts by weight of the adhesive composition.

As mentioned above, each of the adhesive composition and the adhesivefilm of the present invention comprises a composition comprising (a) anepoxy resin, (b) a curing agent, (c) a polymer compound incompatiblewith the epoxy resin, and optionally (d) a filler and/or (e) a curingaccelerator, wherein the components are separated into two phases afterbeing cured as viewed in the cross-section thereof. The term “twophases” used here indicates that the cured product has an islands-in-seastructure. The “islands-in-sea structure” in the present invention meansa ununiform structure comprising a continuous phase (referred to as“sea”) and a dispersed phase (referred to as “islands”) described in,for example, page 16 of “Polymer New Material one point Polymer Alloy”,published by KYORITSU SHUPPAN CO., LTD., as viewed in the cross-sectionof the adhesive composition in a cured state, which is polished andexamined under, e.g., a scanning type electron microscope.

In the present invention, each of the adhesive composition and theadhesive film of the present invention wherein the components thereofare separated into two phases after being cured as viewed in thecross-section thereof is achieved by a composition which comprises anepoxy resin, a cyanate resin, a phenolic resin and a curing agenttherefor, a polymer compound incompatible with the above resin, forexample, an acryl rubber, an acrylonitrile-butadiene rubber, a siliconerubber, polyurethane, polyimide, polyamideimide, and a copolymerizedproduct or a mixture thereof, and optionally a filler and/or a curingaccelerator, or its film-state material (an adhesive film).

In the present invention, from the viewpoint of obtaining excellentadhesion between the sea phase and the islands phase and excellentadhesiveness, it is preferred that the two phases comprise a sea phaseand an islands phase, wherein, a length of an outer periphery of theislands phase represented by S and an area of a cross-sectionrepresented by V, satisfy a relationship represented by the followingformula (1):

S/√{square root over ( )}V>3.6  (1).

Further, from the viewpoint of obtaining further excellent adhesionbetween the sea phase and the islands phase, it is preferred that, inthe above formula (1), the relationship: S/(V^(1/2))>4.0 is satisfied.

In the present invention, each of the adhesive composition and theadhesive film wherein the two phases comprise a sea phase and an islandsphase wherein length S of the outer periphery of the islands phase andcross-sectional area V satisfy the relationship represented byS/(V^(1/2))>3.6 is achieved, for example, by a composition whichcomprises an epoxy resin and a curing agent therefor, and a polymercompound incompatible with the above resin, for example, a phenoxyresin, and a filler and a curing accelerator, or its film-state material(an adhesive film). It is especially preferred that the composition orfilm contains a filler, particularly a filler having an average particlediameter of 0.005 to 0.1 μm. Further, it is preferred that the filler issilica and a surface thereof is coated with an organic substance.

In the present invention, there is provided an adhesive compositionwhich gives a cured product having a storage elastic modulus at 240° C.of 1 to 20 MPa.

The adhesive composition having such properties is achieved by acomposition which comprises, for example, an epoxy resin, a cyanateresin, a phenolic resin, and a curing agent therefor, a polymer compoundincompatible with the above resin, and a filler and a curingaccelerator. It is especially preferred that the composition contains afiller, particularly preferably a filler having an average particlediameter of 0.005 to 0.1 μm.

In the present invention, there is further provided an adhesivecomposition or its film-state material (an adhesive film) wherein, in acured state, it has pores having an average diameter of 0.01 μm to 2 μm,and the volume percentage of the pores is 0.1 to 20% by volume.

The adhesive film of the present invention has pores having an averagediameter of 0.01 to 2.0 μm, more preferably 0.03 to 0.1 μm.

In the present invention, the pores in the adhesive film mean voids,spaces, or gaps, and the average diameter of the pores means a diameterof a sphere when the volume of the pore is converted to that of sphere.

When the average diameter of the pores is less than 0.01 μm or more than2.0 μm, the PCT resistance (suppressing the lowering of the adhesivestrength) may be poor.

The volume percentage of the pores in the adhesive film is 0.1 to 20% byvolume. When the volume percentage is less than 0.1% by volume, theeffect aimed at by formation of the pores is poor and the PCT resistanceis poor. When the volume percentage exceeds 20% by volume, the reflowresistance and PCT resistance are lowered. It is more preferred that thepores are dispersed uniformly.

The volume percentage of the pores is calculated by the followingmethod.

(1) In a view through a scanning type electron microscope (SEM), asquare region, having a side with a length of 100 times the averageparticle diameter of the filler used and which has 50 pores, isselected.(2) The area of the square region and the total area of the 50 pores aredetermined by the following method. A transparent film having a uniformdensity and an even thickness is placed on the SEM photograph, and allthe 50 pores are traced by a pen and the traced portions are cut out.(3) The predetermined area portion (including the 50 pores portions) istraced by a pen in the same manner as in Item (2) above, and the tracedportion is cut out.(4) The weight of each of the cut out portions obtained in Items (2) and(3) above is measured to determine a (2)/(3) value.(5) V=[(2)/(3)]^(3/2) is determined.(6) The sequence of the operations in Items (1) to (5) above is repeatedfive times, and an average of V values obtained is taken as a volumepercentage.

It is especially preferred that each of the adhesive composition and theadhesive film of the present invention comprises a cured product of acomposition which comprises (a) an epoxy resin, (b) a curing agent, (c)a polymer compound incompatible with the epoxy resin, and optionally (d)a filler and (e) a curing accelerator, wherein each of them has poreshaving an average diameter of 0.01 to 2.0 μm, and the volume percentageof the pores in the composition or film cured is 0.1 to 20% by volume.

In addition, in the present invention, there is provided an adhesivefilm which limits lowering in flow after 72 hours at 60° C. of 50% orless.

When the lowering in flow of the adhesive film is 50% or less, theadhesive film can be advantageously stored at 25° C. or 5° C. for a longterm, enabling a long storage. The lowering in flow can be measuredaccording to the following procedure.

First, an adhesive film is punched out into a sample having a size of 1cm×2 cm and pressed under conditions such that the temperature is 160°C., the pressure is 1 MPa, and the time is 18 seconds. With respect tofour samples, lengths of portions squeezed out from the original sizeare measured at two points per each sample by means of an opticalmicroscope to determine an average length, and this value is taken as aflow amount. From the initial flow amount F₍₀₎ and the flow amount F₍₇₂₎after 72 hours at 60° C., the lowering rate of the flow after 72 hoursat 60° C. is determined by the following formula:

Lowering rate of flow (%)=(F ₍₀₎ −F ₍₇₂₎)/F ₍₀₎×100

Further, the adhesive film of the present invention comprises a curedproduct of a composition which comprises (a) an epoxy resin, (b) acuring agent, (c) a polymer compound incompatible with the epoxy resin,(d) a filler, and (e) a curing accelerator, and it is preferred thatcomponents (a) to (e) satisfy the relationship represented by thefollowing formula:

0.75>a/b

-   -   wherein a represents a contact angle of (d) the filler with        water, and b represents a contact angle with water of a material        obtained by coating and drying the composition comprising        components (a), (b), (c) and (e).

The adhesive film having the above-mentioned properties can be achievedby a composition which comprises, for example, an epoxy resin, a cyanateresin, a phenolic resin, a curing agent therefor, a polymer compoundincompatible with the above resin, for example, an acryl rubber, anacrylonitrile-butadiene rubber, a silicone rubber, polyurethane,polyimide, polyamideimide, and a copolymerized product or a mixturethereof, and optionally a filler and/or a curing accelerator, or itsfilm-state material. Especially, the adhesive film is achieved by anadhesive film which comprises an epoxy resin and a curing agenttherefor, an epoxy group-containing acrylic copolymer being incompatiblewith these and containing 1.5 to 2.0% by weight of glycidyl acrylate orglycidyl methacrylate and having a weight average molecular weight of100,000 or more, and a filler and a curing accelerator. It is especiallypreferred to use an epoxy resin having a softening point of 50° C. ormore. Further, it is preferred to use the phenolic resin represented bythe general formula (I) as a curing agent.

It is preferred that the adhesive film of the present invention isobtained by coating and drying the adhesive composition comprising theabove-mentioned components (a) to (e), wherein the components of theabove-mentioned (a) to (e) are selected so that the relationship:0.75>a/b (wherein each of a and b is as defined above) is satisfied.

It is preferred that the relationship: 0.75>a/b is satisfied, that is,a/b is preferably less than 0.75, more preferably less than 0.66,especially preferably less than 0.50. The lower limit of a/b is about0.25.

When a/b is 0.75 or more, the adhesiveness after absorbing moisture maybe poor.

The contact angle a of the filler with water is measured by theabove-mentioned method. With respect to the material obtained byapplying the composition comprising the components (a), (b), (c) and (e)and drying the composition applied, the contact angle b with water ismeasured in the same manner as in contact angle a.

Further, it is preferred that each of the adhesive composition and theadhesive film of the present invention comprises the components (a) to(e) in the following formulation ratios:

49.5 to 17.0% by weight of the sum of (a) the epoxy resin and (b) thecuring agent;50.0 to 70.0% by weight of (c) the polymer compound;0.45 to 10.0% by weight of (d) the filler; and0.05 to 3.0% by weight of (e) the curing accelerator.

It is preferred that the amount of the sum of (a) the epoxy resin and(b) the curing agent is 17.0 to 49.5% by weight. When the amount is lessthan 17.0% by weight, the adhesiveness, the moldability (flowability),etc. tend to be insufficient. On the other hand, when the amount exceeds49.5% by weight, the elastic modulus tends to be too large.

It is preferred that a ratio of (a) the epoxy resin to (b) the curingagent [(a):(b) ratio] is 33:67 to 75:25. When the ratio of the epoxyresin (a) is too large in the above ratio, the heat resistance andmoldability (flowability) tend to be unsatisfactory. When the ratio of(b) the curing agent is too large in the above ratio, the moldability(flowability) tends to be insufficient.

By using the composition having the above-mentioned formulation, anadhesive film excellent in heat resistance after absorbing moisture,reflow resistance, adhesiveness after absorbing moisture, etc. can beobtained.

It is preferred that the adhesive film of the present inventioncomprises the adhesive composition wherein the A/B ratio is 0.24 to 1.0,where A represents the total weight of (a) the epoxy resin and (b) thephenolic resin represented by the above formula (I) and B represents theweight of (c) the acrylic copolymer containing 0.5 to 6% by weight of areactive group-containing monomer and having a weight average molecularweight of 100,000 or more.

In the present invention, there is provided an adhesive film whichcomprises a laminated cured product of the above adhesive compositionand a polyimide film, wherein the laminated cured product has a peelstrength of 50 N/m or more as measured at 240° C. In addition, in thepresent invention, there is provided the adhesive film wherein, when thelaminated cured product is subjected to moisture absorption treatmentand then subjected to heat treatment at 260° C. for 120 seconds, theresultant laminated cured product does not suffer peeling with adiameter of 2 mm or more. Further, in the present invention, there isprovided a semiconductor device wherein, when the device is subjected tomoisture absorption treatment at 85° C. and a relative humidity of 85%for 168 hours, and then, passed through a reflow furnace at 260° C. for120 seconds, the resultant device does not suffer peeling with adiameter of 1 mm or more between the adhesive layer and thesemiconductor chip.

Each of the above-mentioned adhesive film and the semiconductor devicecan be achieved by a composition which comprises, for example, an epoxyresin, a cyanate resin, a phenolic resin and a curing agent therefor, apolymer compound being incompatible with these and having acrosslinkable functional group, and optionally a filler and/or a curingaccelerator, and its film-state material and a semiconductor deviceproduced by using these. Especially, it can be achieved by an adhesivefilm which comprises an epoxy resin, a curing agent therefor, an epoxygroup-containing acrylic copolymer being incompatible with these andcontaining 1.5 to 6.0% by weight of glycidyl acrylate or glycidylmethacrylate and having a weight average molecular weight of 100,000 ormore, and a filler and a curing accelerator. It is especially preferredto use an epoxy resin having a softening point of 50° C. or more.Further, it is preferred that the curing agent is a phenolic resinrepresented by the above general formula (I). It is especially preferredto contain a filler having an average particle diameter of 0.005 to 0.1μm. In addition, it is preferred that the filler is silica and has asurface coated with an organic substance.

In the adhesive composition of the present invention, excellent moistureabsorption resistance can be obtained by using the low moistureabsorption phenolic resin represented by the formula (I), excellentreflow crack resistance can be obtained by using an acrylic copolymerwhich contains a reactive group-containing monomer to form a suitablecrosslinked structure, and excellent reflow crack resistance and heatresistance can be obtained by using an acrylic copolymer incompatiblewith the epoxy resin to form a definite islands-in-sea structure afterbeing cured. Further, by adding an inorganic filler, there can beobtained an adhesive composition having high elastic modulus at hightemperatures, an increased peel strength at high temperatures, andexcellent reflow crack resistance by an action of reflow crackprevention.

The adhesive film of the present invention is obtained as an adhesivelayer formed on a support film by a method in which the adhesivecomposition of the present invention is dissolved or dispersed in asolvent such as methyl ethyl ketone, toluene, cyclohexanone, etc. toprepare a varnish, and the prepared varnish is coated to a support filmsuch as a polytetrafluoroethylene film or a polyethylene terephthalatefilm having a release-treated surface, and then heated and dried toremove the solvent.

In this case, preferred conditions for heating are, for example, suchthat the temperature is 80 to 250° C. and the time is about 10 minutesto about 20 hours.

As the support film, a plastic film such as a polytetrafluoroethylenefilm, a polyethylene terephthalate film, a polyethylene film, apolypropylene film, a polymethylpentene film, a polyimide film, etc. canbe used, and the surfaces of these plastic films can be release-treated.

The support film can be peeled off upon use so that the adhesive layer(i.e., an adhesive film) can be used solely, or it can be used with thesupport film and the support film can be peeled off later.

As a method for coating a varnish to a support film, a known method canbe used, and examples include a knife coating method, a roll coatingmethod, a spray coating method, a gravure coating method, a bar coatingmethod, a curtain coating method, etc.

The thickness of the adhesive layer (i.e., an adhesive film) is notparticularly limited, but the thickness is preferably 3 to 300 μm, morepreferably 25 to 250 μm, further preferably 10 to 200 μm, especiallypreferably 20 to 100 μm. When the thickness is thinner than 3 μm, thestress relaxation effect tends to be poor, and, on the other hand, whenthe thickness is thicker than 300 μm, such a thickness isdisadvantageous from an economical point of view.

The solvent for the varnish is not particularly limited, but, from theviewpoint of facilitating volatilization of the solvent during the filmpreparation, it is preferred to use a solvent having a relatively lowboiling point such as methyl ethyl ketone, acetone, methyl isobutylketone, 2-ethoxyethanol, toluene, xylene, butyl cellosolve, methanol,ethanol, 2-methoxyethanol, etc. Further, for the purpose of improvingthe coating properties, a solvent having a relatively high boiling pointsuch as dimethylacetamide, dimethylformamide, N-methylpyrrolidone,cyclohexanone, etc. may be added.

In preparation of the varnish when a filler is added to the adhesivecomposition of the present invention, from the viewpoint ofdispersibility of the filler, it is preferred to use a mixer, athree-roll mill, a ball mill, a beads mill, etc., and these can be usedin combination. Further, the filler and a low molecular compound arepreliminarily mixed with each other, and then, a polymer compound isincorporated thereinto, thereby it is possible to shorten the time formixing. After a varnish is prepared, it is preferred that bubbles in thevarnish are removed by vacuum deaeration.

In the present invention, when a filler is added to the adhesivecomposition, it is preferred to employ a method in which an epoxy resin,a curing agent and a filler are mixed with one another, and then, apolymer compound incompatible with the epoxy resin is mixed into theresultant mixture to produce an adhesive composition. By employing theabove production method, a film of the epoxy resin is formed at theinterface of the filler. Therefore, after the rubber and the epoxy resinundergo phase separation and are cured, a larger amount of the fillerremains in the epoxy resin phase, so that the effect of reinforcingadhesion of the interface between the epoxy resin and the filler isincreased, thus improving the heat resistance of the resultant curedproduct. It is preferred that the ratio of the volume VA of the fillercontained in the epoxy resin phase to the volume VB of the fillercontained in the rubber component phase after being cured, i.e., VA/VBis 1.2 or more. When VA/VB is less than 1.2, the effect of reinforcingadhesion of the interface between A and B is unsatisfactory, so that theheat resistance of the cured product tends to be poor. VA/VB isespecially preferably 2 or more, further preferably 4 or more.Incidentally, VA/VB can be measured in accordance with the followingprocedure. The rupture cross-section of a film is observed through ascanning type electron microscope to measure a peak of the atoms whichconstitute the filler by means of an XMA with respect to each of theregions comprised mainly of A and B, respectively. VA/VB is determinedfrom the height ratio between these peaks.

Also, for obtaining a desired thickness of the adhesive layer in theadhesive film of the present inventions two or more films can belaminated to one another. In this case, it is required to set conditionsfor sticking films so that no peeling occurs in the adhesive layers.

The adhesive film of the present invention can be used in the form of anadhesive member formed on both surfaces of a film as a core material.The adhesive member has an advantage in that the film is improved bothin handling properties and punching-out property by a metal mold. It ispreferred that the thickness of the core material is in the range offrom 5 to 200 μm, but the thickness is not limited to this range.

The film used as a core material is not particularly limited, but thefilm is preferably a heat-resistant thermoplastic film, furtherpreferably a heat-resistant thermoplastic film having a softening pointof 260° C. or higher. When a heat-resistant thermoplastic film having asoftening point of lower than 260° C. is used as a core material, theadhesive film is possibly peeled off at high temperatures, i.e., duringsoldering reflow. Further, heat-resistant thermoplastic films usingliquid crystalline polymers, polyamideimide, polyimide, polyetherimide,polyethersulfone, whole aromatic polyester, polytetrafluoroethylene,ethylene-tetrafluoroethylene copolymers,tetrafluoroethylene-hexafluoropropylene copolymers,tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, etc. arepreferably used. Further, as the heat-resistant thermoplastic film, aporous film can be used for reducing the elastic modulus of the adhesivelayer.

The adhesive layers formed on both surfaces of the core material can befirstly made a varnish by dissolving or dispersing an adhesivecomposition in a solvent. The prepared varnish is applied to aheat-resistant thermoplastic film which becomes a core material bycoating, and heated to remove the solvent to form an adhesive film onthe heat-resistant thermoplastic film. As the method for coating, theabove-mentioned methods can be used. This step is conducted with respectto both surfaces of the heat-resistant thermoplastic film to prepare anadhesive film having adhesive layers on both surfaces of the corematerial. In this case, it is preferred that the surfaces of theadhesive film are protected by cover films so that the adhesive layerson both surfaces do not suffer blocking. However, when no blockingoccurs, it is preferred not to use a cover film from an economical pointof view, and there is no limitation.

Also, a varnish prepared by dissolving or dispersing an adhesivecomposition in a solvent, and the prepared varnish is applied to theabove-mentioned support film, and heated to remove the solvent to forman adhesive layer on the support material. The adhesive layers arelaminated to both surfaces of a core material to prepare an adhesivefilm having adhesive layers formed on both surfaces of the corematerial. In this case, the support film can be used as a cover film.

The substrate for mounting semiconductor of the present invention is notlimited by substrate materials such as a lead frame having a die pad,ceramic substrates, and organic substrates. As ceramic substrates,alumina substrates and aluminum nitride substrates can be used. Asorganic substrates, FR-4 substrates obtained by impregnating an epoxyresin into glass cloth, BT substrates obtained by impregnating abismaleimide-triazine resin into glass cloth, and polyimide filmsubstrates using a polyimide film as a base material can be used.

As the shape of wiring, any structure of single side wiring, both sideswiring, and multilayer wiring may be used, and, if desired, anelectrically connected through hole or non-through hole may be formed.

Further, when the wiring appears on the outer surface of thesemiconductor device, it is preferred to form a protecting resin layer.

As a method for laminating an adhesive film to a supporting member, amethod in which the adhesive film is cut into a desired shape, and thecut adhesive film is heat-pressed to the supporting member at a desiredposition is general, but the method is not limited to this one.

The semiconductor device in which a semiconductor chip and a wiringboard are adhered to each other can be produced by placing an adhesivefilm between a semiconductor chip and a wiring board so that the firstadhesive layer is faced to the surface of the semiconductor chip side,and heat-pressing the resultant laminated material. Also, asemiconductor chip may be placed on the wiring board for mountingsemiconductor equipped with the above-mentioned adhesive film and thenheat-pressed. The process for producing a semiconductor device in whichan adhesive film and a dicing tape are laminated to a semiconductorwafer, and then, the resultant wafer and adhesive film are cut into achip, and a substrate having a circuit or a film having a circuit andthe chip are adhered through an adhesive film is preferred from theviewpoint of omitting the steps of attaching the adhesive films on eachof the chip.

As examples of structures of the semiconductor device of the presentinvention, there can be mentioned a structure such that an electrode ofa semiconductor element and a supporting member for the semiconductorare connected to each other through wire bonding, and a structure suchthat an electrode of a semiconductor element and a supporting member areconnected to each other through inner lead bonding of tape automatedbonding (TAB), etc., but the structure is not limited to these, and aneffect can be obtained by any of these structures.

In the process for producing a semiconductor device in which asemiconductor chip and a substrate having a circuit or a film having acircuit are laminated together with an adhesive film, the conditions forheat press may be such that the temperature, load, and time are selectedso that the circuit for wiring board is embedded without a space andsatisfactory adhesiveness are exhibited. From the viewpoint ofpreventing the chip damage, the load is preferably 196 kPa or less,especially preferably 98 kPa or less.

As the semiconductor element, general semiconductor elements such as IC,LSI, VLSI, etc. can be used.

The thermal stress caused between the semiconductor element and thesupporting member is significant when the difference in area between thesemiconductor element and the supporting member is small, but, in thesemiconductor device of the present invention, by using an adhesive filmhaving a low elastic modulus, the thermal stress is relaxed to ensurereliability. These effects are very effectively exhibited when the areaof the semiconductor element is 70% or more of the area of thesupporting member. Also, in such a semiconductor device in which thedifference in area between the semiconductor element and the supportingmember is small, external connection terminals are often formed in anarea form.

Also, the characteristic feature of the adhesive film of the presentinvention resides in that an amount of the volatile components from theadhesive layer can be reduced in steps in which the adhesive film isheated such as the step of heat-pressing the adhesive film to thesupporting member at a desired position and the step of connectingthrough wire bonding.

The wiring board used in the wiring board for mounting semiconductorequipped with the adhesive film of the present invention is not limitedby materials of the substrate such as ceramic substrates and organicsubstrates. For example, as ceramic substrates, alumina substrates andaluminum nitride substrates can be used. As organic substrates, FR-4substrates obtained by impregnating an epoxy resin into glass cloth, BTsubstrates obtained by impregnating a bismaleimidetriazine resin intoglass cloth, and polyimide film substrates using a polyimide film as abase material can be used.

As the shape of wiring, any structures of single side wiring, both sideswiring, and multilayer wiring may be used, and, if desired, anelectrically connected through hole or non-through hole may be formed.

Further, when the wiring appears on the outer surface of thesemiconductor device, it is preferred to form a protecting resin layer.

As a method for laminating an adhesive film to a wiring board, a methodin which the adhesive film is cut into a desired shape, and the cutadhesive film is heat-pressed to the wiring board at a desired positionis general, but the method is not limited to this Examples.

EXAMPLES

In the following, the present invention will be explained in more detailby referring to the following Examples, but the present invention is notlimited by these.

Example 1 Sample 1

Methyl ethyl ketone was added to Adhesive composition 1 comprising 61parts by weight of an o-cresol novolak type epoxy resin: YDCN-703(manufactured by Tohto Kasei Co., Ltd.; trade name; epoxy equivalent:210), 39 parts by weight of a bisphenol A novolak resin: Plyofen LF2882(manufactured by Dainippon Ink & Chemicals, Inc.; trade name), 150 partsby weight of an epoxy group-containing acrylic rubber: HTR-860P-3(manufactured by Teikoku Chemical Industries Co., Ltd.; trade name;molecular weight: 1,000,000; Tg: −7° C.), and, as curing agents, 0.5part by weight of 1-cyanoethyl-2-phenylimidazole: Curezol 2PZ-CN(manufactured by Shikoku Kasei Kogyo Co.; trade name) and 0.7 part byweight of γ-glycidoxypropyltrimethoxysilane: NUC A-187 (trade name;manufactured by Nippon Unicar Co., Ltd.), was added, and mixed bystirring, followed by vacuum deaeration.

The adhesive varnish was coated onto a release-treated polyethyleneterephthalate film having a thickness of 75 μm, and dried by heating at140° C. for 5 minutes to form a coating film in a B-stage having athickness of 75 μm, thus preparing an adhesive film (Adhesive film 1)equipped with a support film.

When the adhesive film was stored in an atmosphere at 25° C. at 50% RH(a relative humidity), after one day, the flow amount was 390 μm and theadhesive strength was 620 N/m; after 30 days, the flow amount was 170 μmand the adhesive strength was 550 N/m; and, after 90 days, the flowamount was 35 μm and the adhesive strength was 280 N/m. The flow amountwas determined as follows. A film-form adhesive having a thickness of 75μm was punched out by a 10 mm φ punch, and placed at a center portionbetween two sheets of polyethylene terephthalate films cut to 25 mm×25mm, and pressed under conditions at 100° C. and 3 MPa for 5 minutes, andthen, the size of the resultant sample was measured to determine thedifference in the radius of the sample before and after pressing. Also,the peel strength was determined as follows. 50 μm polyimide films(UPILEX S (Tg: 500° C. or higher), trade name, manufactured by UbeIndustries Ltd. was used) were laminated to both surfaces of thefilm-form adhesive using a hot roll laminator under conditions at atemperature of 100° C., a pressure of 0.3 MPa and a speed of 0.3 m/min,and then cured at a temperature of 170° C. for one hour. The polyimidefilms on the both surfaces of the sample cut into 10 mm width wereindividually supported, and a T-peel strength was measured in anatmosphere at room temperature at a speed of 50 mm/min in the directionof 180 degrees.

Further, a storage elastic modulus of the adhesive composition obtainedby curing the adhesive film at 170° C. for one hour was measured byusing a dynamic viscoelasticity measuring machine (manufactured byRheology, DVE-V4) (sample size: length: 20 mm, width: 4 mm, thickness:80 μm; temperature elevation rate: 5° C./min; tensile mode: 10 Hz;automatic static loading). As a result, it was 380 MPa at 25° C. and 5MPa at 260° C.

The above-mentioned Adhesive film 1 was allowed to stand for two minuteson a hot platen heated to a predetermined temperature, and thedifference in the weight of the film before and after heating wasdetermined to calculate a volatile content according to the followingformula:

Volatile content (% by weight)=({[Weight (g) of adhesive film beforeheating]−[Weight (g) of adhesive film after heating]}/[Weight (g) ofadhesive film before heating])×100

The above-mentioned Adhesive films 1 were laminated together using a hotroll laminator under conditions at a temperature of 110° C., a pressureof 0.3 MPa and a speed of 0.3 m/min to prepare an adhesive member havinga thickness of 150 μm in a single-layer film form.

By using the obtained adhesive member, a semiconductor chip and a wiringboard using a polyimide film having a thickness of 25 μm as a supportwere laminated together to prepare a semiconductor device sample (havingsolder balls formed on one surface thereof; Sample 1), and theislands-in-sea structure, heat resistance, flame retardancy, andmoisture resistance were examined.

The semiconductor device sample was prepared by the following method.That is, the obtained adhesive film was heat-pressed to a wiring boardusing a polyimide film having a thickness of 50 μm as a base material,and a semiconductor chip having a size of 15×7 mm was furtherheat-pressed thereonto, and then, the adhesive film was cured. The endsurface of the adhesive film was further partially encapsulated by anencapsulating material (manufactured by Hitachi Chemical Co., Ltd.,CEL-C-4100, trade name) to prepare a semiconductor device sample shownin FIG. 1.

With respect to the islands-in-sea structure, the cross-section of thecured product was observed through a scanning type electron microscopeto measure a value obtained from the relationship (S/V^(1/2)) betweenlength S of the outer periphery of the islands phase and cross-sectionalarea V. As the evaluation method for heat resistance, an evaluation ofreflow crack resistance and a temperature cycle test were used. Theevaluation of the reflow crack resistance was made as follows. A samplewas placed in an IR reflow furnace in which the temperature was adjustedso that the maximum temperature of the sample surface became 240° C. andthis temperature was kept for 20 seconds, and then cooled by allowingthe sample to stand at room temperature. The sequence of the abovetreatments was repeated two times, and then, the resultant sample wasobserved by visual examination and through an ultrasonic microscope inrespect of crack. A sample in which no crack was observed was rated “◯”,and a sample in which a crack was observed was rated “X”. The evaluationof the temperature cycle resistance was made as follows. A sample wasallowed to stand in an atmosphere at −55° C. for 30 minutes and thenstand in an atmosphere at 125° C. for 30 minutes. The sequence of theabove treatments was repeated 1,000 cycles, and then the resultantsample was observed through an ultrasonic microscope in respect ofdamage such as an occurrence of peeling or crack. A sample in which nodamage was observed was rated “◯”, and a sample in which a damage wasobserved was rated “X”. In addition, the evaluation of the moistureresistance was made as follows. A sample was treated in an atmosphere ata temperature of 121° C. at a humidity of 100% at 2.03×10⁵ Pa (pressurecooker test, PCT treatment) for 72 hours, and then the resultant samplewas observed in respect of peeling. A sample in which no peeling wasrecognized in the adhesive member was rated “◯”, and a sample in whichpeeling was recognized in the adhesive member was rated “X”.

Sample 2

Methyl ethyl ketone was added to Adhesive composition 2 comprising 32.5parts by weight of a bisphenol A type epoxy resin: EPIKOTE 1001(manufactured by Japan Epoxy Resins Co., Ltd.; trade name; epoxyequivalent: 475), 35.8 parts by weight of an o-cresol novolak type epoxyresin: YDCN-703 (manufactured by Tohto Kasei Co., Ltd.; trade name;epoxy equivalent: 210), 31.7 parts by weight of a bisphenol A novolakresin: Plyofen LF2882 (manufactured by Dainippon Ink & Chemicals, Inc.,trade name), 150 parts by weight of an epoxy group-containing acrylicrubber: HTR-860P-3 (manufactured by Teikoku Chemical Industries Co.,Ltd.; trade name; molecular weight: 1,000,000; Tg: −7° C.), and, ascuring agents, 0.5 part by weight of 1-cyanoethyl-2-phenylimidazole:Curezol 2PZ-CN (manufactured by Shikoku Kasei Kogyo Corporation, tradename) and 0.7 part by weight of γ-glycidoxypropyltrimethoxysilane: NUCA-187 (manufactured by Nippon Unicar Co., Ltd., trade name), and mixedby stirring, followed by vacuum deaeration.

The adhesive varnish was coated onto a release-treated polyethyleneterephthalate film having a thickness of 75 μm, and dried by heating at140° C. for 5 minutes to form a coating film in a B-stage having athickness of 75 μm, thus preparing an adhesive film (Adhesive film 2)equipped with a support film.

When the adhesive film was stored in an atmosphere at 25° C. at 50% RH(a relative humidity) after one day, the flow amount was 480 μm and theadhesive strength was 600 N/m; after 30 days, the flow amount was 220 μmand the adhesive strength was 540 N/m; and, after 90 days, the flowamount was 35 μm and the adhesive strength was 260 N/m. The flow amountwas determined as follows. A film-form adhesive having a thickness of 75μm was punched out by a 10 mm φ punch, and placed at a center portionbetween two sheets of polyethylene terephthalate films cut to 25 mm×25mm, and pressed under conditions at 100° C. and 3 MPa for 5 minutes, andthen, the size of the resultant sample was measured to determine thedifference in the radius of the sample before and after pressing. Also,the peel strength was determined as follows. 50 μm polyimide films(UPILEX S; manufactured by Ube Industries Ltd., trade name) werelaminated to both surfaces of the film-form adhesive using a hot rolllaminator under conditions at a temperature of 100° C., a pressure of0.3 MPa and a speed of 0.3 m/min, and then cured at a temperature of170° C. for one hour. The polyimide films on the both surfaces of thesample cut into 10 mm width were individually supported, and a T-peelstrength was measured in an atmosphere at room temperature at a speed of50 mm/min in the direction of 180 degrees.

Further, a storage elastic modulus of the adhesive composition obtainedby curing the adhesive film at 170° C. for one hour was measured byusing a dynamic viscoelasticity measuring machine DVE-V4 (manufacturedby Rheology, trade name) (sample size: length: 20 mm, width: 4 mm,thickness: 80 μm; temperature elevation rate: 5° C./min; tensile mode;10 Hz; automatic static loading). As a result, it was 370 MPa at 25° C.and 5 MPa at 260° C.

Then, substantially the same procedure as in the preparation of Sample 1was conducted except that Adhesive film 1 was changed to Adhesive film 2to prepare a semiconductor device sample (Sample 2), and the sample wasevaluated in the same manner as in sample 1. The results of evaluationare shown in Table 1.

Sample 3

Methyl ethyl ketone was added to Adhesive composition 3 comprising 45parts by weight of a bisphenol A type epoxy resin: EPIKOTE 828(manufactured by Japan Epoxy Resins Co., Ltd.; trade name; epoxyequivalent: 190), 15 parts by weight of an o-cresol novolak type epoxyresin: ESCN195 (manufactured by Sumitomo Chemical Co., Ltd.; trade name;epoxy equivalent: 195), 40 parts by weight of a bisphenol A novolakresin: Plyofen LF2882 (manufactured by Dainippon Ink & Chemicals, Inc.,trade name), 150 parts by weight of an epoxy group-containing acrylicrubber: HTR-860P-3 (manufactured by Teikoku Chemical Industries Co.,Ltd.; trade name; molecular weight: 1,000,000; Tg: −7° C.), and, ascuring agents, 0.5 part by weight of 1-cyanoethyl-2-phenylimidazole:Curezol 2PZ-CN (manufactured by Shikoku Kasei Kogyo Corporation, tradename) and 0.7 part by weight of γ-glycidoxypropyltrimethoxysilane: NUCA-187 (trade name; manufactured by Nippon Unicar Co., Ltd.), and mixedby stirring, followed by vacuum deaeration.

The adhesive varnish was coated onto a release-treated polyethyleneterephthalate film having a thickness of 75 μm, and dried by heating at140° C. for 5 minutes to form a coating film in a B-stage having athickness of 75 μm, thus preparing an adhesive film (Adhesive film 3)equipped with a support film.

When the adhesive film was stored in an atmosphere at 25° C. at 50% RH(a relative humidity), after one day, the flow amount was 400 μm and theadhesive strength was 600 N/m; after 30 days, the flow amount was 180 μmand the adhesive strength was 500 N/m; and, after 90 days, the flowamount was 30 μm and the adhesive strength was 250 N/m. The flow amountwas determined as follows. A film-form adhesive having a thickness of 75μm was punched out by a 10 mm φ punch, and placed at a center portionbetween two sheets of polyethylene terephthalate films cut to 25 mm×25mm, and pressed under conditions at 100° C. and 3 MPa for 5 minutes, andthen, the size of the resultant sample was measured to determine thedifference in the radius of the sample before and after pressing. Also,the peel strength was determined as follows, 50 μm polyimide films(UPILEX S; manufactured by Ube Industries Ltd., trade name) werelaminated to both surfaces of the film-form adhesive using a hot rolllaminator under conditions at a temperature of 100° C., a pressure of0.3 MPa and a speed of 0.3 m/min, and then cured at a temperature of170° C. for one hour. The polyimide films on the both surfaces of thesample cut into 10 mm width were individually supported, and a T-peelstrength was measured in an atmosphere at room temperature at a speed of50 mm/min in the direction of 180 degrees.

Further, a storage elastic modulus of the adhesive composition obtainedby curing the adhesive film at 170° C. for one hour was measured byusing a dynamic viscoelasticity measuring machine DVE-V4 (manufacturedby Rheology, trade name) (sample size: length: 20 mm, width: 4 mm,thickness: 80 μm; temperature elevation rate: 5° C./min; tensile mode;10 Hz; automatic static loading). As a result, it was 360 MPa at 25° C.and 4 MPa at 260° C.

Then, substantially the same procedure as in the preparation of sample 1was conducted except that Adhesive film 1 was changed to Adhesive film 3to prepare a semiconductor device sample (Sample 3), and the sample wasevaluated in the same manner as in sample 1. The results of evaluationare shown in Table 1.

Sample 4

Methyl ethyl ketone was added to Adhesive composition 4 comprising 45parts by weight of a bisphenol A type epoxy resin: EPIKOTE 828(manufactured by Japan Epoxy Resins Co., Ltd.; trade name; epoxyequivalent: 190), 15 parts by weight of an o-cresol novolak type epoxyresin: ESCN195 (manufactured by Sumitomo Chemical Co., Ltd.; trade name;epoxy equivalent: 195), 40 parts by weight of a bisphenol A novolakresin: Plyofen LF2882 (manufactured by Dainippon Ink & Chemicals, Inc.,trade name), 150 parts by weight of an acrylic rubber containing noepoxy group: HTR-860-3DR(A) (manufactured by Teikoku Chemical IndustriesCo., Ltd.; trade name; molecular weight: 1,000,000; Tg: −7° C.), and, ascuring agents, 0.5 part by weight of 1-cyanoethyl-2-phenylimidazole:Curezol 2PZ-CN (manufactured by Shikoku Corporation, trade name) and 0.7part by weight of γ-glycidoxypropyltrimethoxysilane: NUC A-187(manufactured by Nippon Unicar Co., Ltd., trade name), and mixed bystirring, followed by vacuum deaeration.

The adhesive varnish was coated onto a release-treated polyethyleneterephthalate film having a thickness of 75 μm, and dried by heating at140° C. for 5 minutes to form a coating film in a B-stage having athickness of 75 μm, thus preparing an adhesive film (Adhesive film 4)equipped with a support film. When the adhesive film was stored in anatmosphere at 25° C. at 50% RH (a relative humidity), after one day, theflow amount was 400 μm and the adhesive strength was 600 N/m; after 30days, the flow amount was 180 μm and the adhesive strength was 500 N/m;and, after 90 days, the flow amount was 30 μm and the adhesive strengthwas 250 N/m. The flow amount was determined as follows.

Further, a storage elastic modulus of the adhesive composition obtainedby curing the adhesive film at 170° C. for one hour was measured byusing a dynamic viscoelasticity measuring machine DVE-V4 (manufacturedby Rheology, trade name) (sample size: length: 20 mm, width: 4 mm,thickness: 80 μm; temperature elevation rate: 5° C./min; tensile mode;10 Hz; automatic static loading). As a result, it was 400 MPa at 25° C.and 1 MPa at 260° C.

Then, substantially the same procedure as in the preparation of sample 1was conducted except that Adhesive film 1 was changed to Adhesive film 4to prepare a semiconductor device sample (Sample 4), and the sample wasevaluated in the same manner as in sample 1. The results of evaluationare shown in Table 1.

TABLE 1 Item Sample 1 Sample 2 Sample 3 Sample 4 Compatibility Incom-Incom- Incom- Incom- patible patible patible patible Adhesive film 1 2 34 S/(V^(1/2)) 3.55 3.55 3.55 3.55 Volatile Hot platen: 0 0 0.55 0.48content (% 140° C. by weight) Hot platen: 0.02 0.05 0.64 0.59 160° C.Hot platen: 0.07 0.09 0.90 0.84 180° C. Hot platen: 0.30 0.42 1.34 1.29230° C. Hot platen: 0.52 0.56 1.85 1.77 250° C. Hot platen: 0.80 0.902.60 2.51 270° C. Heat Reflow ◯ ◯ ◯ X resistance crack resistanceTemperature ◯ ◯ ◯ X cycle resistance Moisture resistance ◯ ◯ ◯ ◯

From Table 1, it is apparent that the adhesive composition of thepresent invention has a small volatile content and has excellent heatresistance and moisture resistance when being in a B-stage. In addition,it is apparent that more excellent performance can be obtained by usinga solid epoxy resin having a softening point of 50° C. or more. Further,it is apparent that, by using a compound containing an epoxy group as apolymer compound, an adhesive member, a substrate for mountingsemiconductors and a semiconductor device each having more excellentheat resistance can be provided.

Example 2 Sample 5

Methyl ethyl ketone was added to a composition comprising 45 parts byweight of EPIKOTE 828 (manufactured by Japan Epoxy Resins Co., Ltd.;trade name, bisphenol A type epoxy resin; epoxy equivalent: 190), 15parts by weight of ESCN195 (manufactured by Sumitomo Chemical Co., Ltd.;trade name, cresol novolak type epoxy resin; epoxy equivalent: 195),54.6 parts by weight of Milex XLC-LL (manufactured by Mitsui Chemicals,Inc.; trade name, zylok (phenolic) resin (condensation product ofaralkyl ether with phenol); hydroxyl equivalent: 174), 15 parts byweight of Pheienot YP-50 (manufactured by Tohto Kasei Co., Ltd.; tradename, phenoxy resin; molecular weight: 50,000), 150 parts by weight ofHTR-860P-3 (manufactured by Teikoku Chemical Industries Co., Ltd.; tradename, epoxy group-containing acrylic rubber; molecular weight:1,000,000; Tg: −7° C.), 0.5 part by weight of Curezol 2PZ-CN(manufactured by Shikoku Kasei Kogyo Corporation; trade name,1-cyanoethyl-2-phenylimidazole), and 0.7 part by weight of NUC A-187(manufactured by Nippon Unicar Co., Ltd.; trade name,γ-glycidoxypropyltrimethoxysilane), and mixed by stirring, followed byvacuum deaeration. The adhesive varnish was coated onto arelease-treated polyethylene terephthalate film having a thickness of 75μm, and dried by heating to 140° C. for 5 minutes to obtain adhesivefilm (F-1) in a B-stage having a thickness of 75 μm. When the obtainedadhesive film was stored in an atmosphere at 25° C. at 50% RH (arelative humidity), after one day, the flow amount was 380 μm and theadhesive strength was 600 N/m; after 30 days, the flow amount was 170 μmand the adhesive strength was 500 N/m; and, after 90 days, the flowamount was 25 μm and the adhesive strength was 250 N/m. The flow amountwas determined as follows. A film-form adhesive having a thickness of 75μm was punched out by a 10 mm φ punch, and placed at a center portionbetween two sheets of polyethylene terephthalate films cut to 25 mm×25mm, and pressed under conditions at 100° C. and 3 MPa for 5 minutes, andthen, the size of the resultant sample was measured to determine thedifference in the radius of the sample before and after pressing. Also,the peel strength was determined as follows. 50 μm polyimide films(manufactured by Ube Industries Ltd., trade name: UPILEX S) werelaminated to both surfaces of the film-form adhesive using a hot rolllaminator under conditions at a temperature of 100° C., a pressure of0.3 MPa and a speed of 0.3 m/min, and then cured at a temperature of170° C. for one hour. The polyimide films (UPILEX) on the both surfacesof the sample cut into 10 mm width were individually supported, and aT-peel strength was measured in an atmosphere at room temperature at aspeed of 50 mm/min in the direction of 180 degrees. Further, a storageelastic modulus of the adhesive composition obtained by curing theadhesive film at 170° C. for one hour was measured by using a dynamicviscoelasticity measuring machine (manufactured by Rheology, DVE-V4)(sample size: length: 20 mm, width: 4 mm, thickness: 80 μm; temperatureelevation rate: 5° C./min; tensile mode: 10 Hz; automatic staticloading). As a result, it was 400 MPa at 25° C. and 8 MPa at 260° C.

In addition, the cross-section of the sample was observed through ascanning type electron microscope. As a result, it was found that avalue obtained from the relationship (S/V^(1/2)) between length S of theouter periphery of the islands phase and cross-sectional area V is 4.5.

Sample 6

Methyl ethyl ketone was added to a composition comprising 15 parts byweight of YD8125 (manufactured by Tohto Kasei Co., Ltd.; trade name,bisphenol A type epoxy resin; epoxy equivalent: 175), 45 parts by weightof YDCN703 (manufactured by Tohto Kasei Co., Ltd.; trade name, cresolnovolak type epoxy resin; epoxy equivalent: 210), 52 parts by weight ofMilex XLC-LL (manufactured by Mitsui Chemicals, Inc.; trade name, zylokresin; hydroxyl equivalent: 174), 15 parts by weight of Pheienot YP-50(manufactured by Tohto Kasei Co., Ltd.; trade name, phenoxy resin;molecular weight: 50,000), 150 parts by weight of HTR-860P-3(manufactured by Teikoku Chemical Industries Co., Ltd.; trade name,epoxy group-containing acrylic rubber; molecular weight: 1,000,000; Tg:−7° C.), 0.5 part by weight of Curezol 2PZ-CN (manufactured by ShikokuKasei Kogyo Corporation; trade name, 1-cyanoethyl-2-phenylimidazole),and 0.7 part by weight of NUC A-187 (manufactured by Nippon Unicar Co.,Ltd.; trade name, γ-glycidoxypropyltrimethoxysilane), and mixed bystirring, followed by vacuum deaeration. The resultant adhesive varnishwas coated onto a release-treated polyethylene terephthalate film havinga thickness of 75 μm, and dried by heating at 140° C. for 5 minutes toobtain Adhesive film (F-2) in a B-stage having a thickness of 75 μm.When the obtained adhesive film was stored in an atmosphere at 25° C. at50% RH (a relative humidity), after one day, the flow amount was 400 μmand the adhesive strength was 620 N/m; after 30 days, the flow amountwas 180 μm and the adhesive strength was 510 N/m; and, after 90 days,the flow amount was 30 μm and the adhesive strength was 280 N/m. Theflow amount was determined as follows. A film-form adhesive having athickness of 75 μm was punched out by a 10 mm φ punch, and placed at acenter portion between two sheets of polyethylene terephthalate filmscut to 25 mm×25 mm, and pressed under conditions at 100° C. and 3 MPafor 5 minutes, and then, the size of the resultant sample was measuredto determine the difference in the radius of the sample before and afterpressing. Also, the peel strength was determined as follows. 50 μmpolyimide films (manufactured by Ube Industries Ltd., trade name: UPILEXS) were laminated to both surfaces of the film-form adhesive using a hotroll laminator under conditions at a temperature of 100° C., a pressureof 0.3 MPa and a speed of 0.3 m/min, and then cured at a temperature of170° C. for one hour. The polyimide films (UPILEX) on the both surfacesof the sample cut into 10 mm width were individually supported, and aT-peel strength was measured in an atmosphere at room temperature at aspeed of 50 mm/min in the direction of 180 degrees. Further, a storageelastic modulus of the adhesive composition obtained by curing theadhesive film at 170° C. for one hour was measured by using a dynamicviscoelasticity measuring machine (manufactured by Rheology, DVE-V4)(sample size: length: 20 mm, width: 4 mm, thickness: 80 μm; temperatureelevation rate: 5° C./min; tensile mode: 10 Hz; automatic staticloading). As a result, it was 420 MPa at 25° C. and 10 MPa at 260° C.

Sample 7

Methyl ethyl ketone was added to a composition comprising 15 parts byweight of YD8125 (manufactured by Tohto Kasei Co., Ltd.; trade name,bisphenol A type epoxy resin; epoxy equivalent: 175), 45 parts by weightof YDCN703 (manufactured by Tohto Kasei Co., Ltd.; trade name, cresolnovolak type epoxy resin; epoxy equivalent: 210), 50 parts by weight ofMilex XLC-4L (manufactured by Mitsui Chemicals, Inc.; trade name, zylokphenolic resin (condensation product of aralkyl ether with phenol);hydroxyl equivalent: 169), 15 parts by weight of Pheienot YP-50(manufactured by Tohto Kasei Co., Ltd.; trade name, phenoxy resin;molecular weight: 50,000), 150 parts by weight of HTR-860P-3(manufactured by Teikoku Chemical Industries Co., Ltd.; trade name,epoxy group-containing acrylic rubber; molecular weight: 1,000,000; Tg:−7° C.), 0.5 part by weight of Curezol 2PZ-CN (trade name, manufacturedby Shikoku Kasei Kogyo Corporation; 1-cyanoethyl-2-phenylimidazole), and0.7 part by weight of NUC A-187 (trade name, manufactured by NipponUnicar Co., Ltd.; γ-glycidoxypropyltrimethoxysilane), and mixed bystirring, followed by vacuum deaeration. The adhesive varnish was coatedonto a release-treated polyethylene terephthalate film having athickness of 75 μm, and dried by heating at 140° C. for 5 minutes toobtain Adhesive film (F-3) in a B-stage having a thickness of 75 μm.When the obtained adhesive film was stored in an atmosphere at 25° C. at50% RH (a relative humidity), after one day, the flow amount was 3,700μm and the adhesive strength was 580 N/m; after 30 days, the flow amountwas 150 μm and the adhesive strength was 480 N/m; and, after 90 days,the flow amount was 23 μm and the adhesive strength was 250 N/m. Theflow amount was determined as follows. A film-form adhesive having athickness of 75 m was punched out by a 10 mm φ punch, and placed at acenter portion between two sheets of polyethylene terephthalate filmscut to 25 mm×25 mm, and pressed under conditions at 100° C. and 3 MPafor 5 minutes, and then, the size of the resultant sample was measuredto determine the difference in the radius of the sample before and afterpressing. Also, the peel strength was determined as follows. 50 μmpolyimide films (manufactured by Ube Industries Ltd., trade name: UPILEXS) were laminated to both surfaces of the film-form adhesive using a hotroll laminator under conditions at a temperature of 100° C., a pressureof 0.3 MPa and a speed of 0.3 m/min, and then cured at a temperature of170° C. for one hour. The polyimide films (UPILEX) on the both surfacesof the sample cut into 10 mm width were individually supported, and aT-peel strength was measured in an atmosphere at room temperature at aspeed of 50 mm/min in the direction of 180 degrees. Further, a storageelastic modulus of the adhesive composition obtained by curing theadhesive film at 170° C. for one hour was measured by using a dynamicviscoelasticity measuring machine (manufactured by Rheology, DVE-V4)(sample size: length: 20 mm, width: 4 mm, thickness: 80 μm; temperatureelevation rate: 5° C./min; tensile mode: 10 Hz; automatic staticloading). As a result, it was 360 MPa at 25° C. and 7 MPa at 260° C.

Sample 8

Substantially the same procedure as in the preparation of Sample 5 wasconducted except that, instead of 54.6 parts by weight of Milex XLC-LL,37 parts by weight of Plyofen LF2882 (manufactured by Dainippon Ink &Chemicals, Inc.; trade name, bisphenol A novolak resin; hydroxylequivalent: 118) was used to obtain Adhesive film (F-4) in a B-stagehaving a thickness of 75 μm. Properties of the adhesive film wereevaluated under the same conditions as those in Example 1. As a result,it was found that, after one day, the flow amount was 380 μm and theadhesive strength was 600 N/m; after 30 days, the flow amount was 180 μmand the adhesive strength was 500 N/m; and, after 90 days, the flowamount was 30 μm and the adhesive strength was 250 N/m. Further, astorage elastic modulus of the cured product of the adhesive was 360 MPaat 25° C. and 4 MPa at 260° C.

Sample 9

Substantially the same procedure as in the preparation of Sample 6 wasconducted except that, instead of 52 parts by weight of Milex XLC-LL, 35parts by weight of Plyofen LF2882 (manufactured by Dainippon Ink &Chemicals, Inc.; trade name, bisphenol A novolak resin; hydroxylequivalent: 118) was used to obtain Adhesive film (F—S) in a B-stagehaving a thickness of 75 μm. With respect to the obtained adhesive film,properties were evaluated under the same conditions as those inExample 1. As a result, it was found that, after one day, the flowamount was 500 μm and the adhesive strength was 750 N/m; after 30 days,the flow amount was 250 μm and the adhesive strength was 600 N/m; and,after 90 days, the flow amount was 40 μm and the adhesive strength was450 N/m. Further, a storage elastic modulus of the cured product of theadhesive was 350 MPa at 25° C. and 4 MPa at 260° C.

Sample 10

Substantially the same procedure as in the preparation of Sample 5 wasconducted except that, instead of the epoxy group-containing acrylicrubber, HTR-860P-3, manufactured by Teikoku Chemical Industries Co.,Ltd., an acrylic rubber containing no epoxy group (molecular weight:1,000,000) and having a composition such that glycidyl methacrylate isremoved from HTR-860P-3 was used to obtain Adhesive film (F-6) in aB-stage having a thickness of 75 μm. Properties of the adhesive filmwere evaluated under the same conditions as those in Example 1. As aresult, it was found that, after one day, the flow amount was 400 μm andthe adhesive strength was 600 N/m; after 30 days, the flow amount was180 μm and the adhesive strength was 500 N/m; and, after 90 days, theflow amount was 30 μm and the adhesive strength was 250 N/m. Further, astorage elastic modulus of the cured product of the adhesive was 400 MPaat 25° C. and 1 MPa at 260° C.

Adhesive films (F-1) to (F-6) in a B-stage obtained in the preparationsof Samples 5 to 10 were individually allowed to stand for 2 minutes on ahot platen heated to a predetermined temperature, and the difference inthe weight of the film between before and after heating was determinedto calculate a volatile content according to the formula shown inExample 1. The results are shown in Table 2.

TABLE 2 Item Sample 5 Sample 6 Sample 7 Sample 8 Sample 9 Sample 10Compatibility Incompatible Incompatible Incompatible IncompatibleIncompatible Incompatible Adhesive film F-1 F-2 F-3 F-4 F-5 F-6 VolatileHot platen: 0 0 0 0.55 0.48 0 content 140° C. (% by Hot platen: 0 0 00.64 0.59 0 weight) 160° C. Hot platen: 0.01 0 0 0.90 0.84 0.08 180° C.Hot platen: 0.05 0.01 0.02 1.34 1.29 0.09 230° C. Hot platen: 0 0 0 0.550.48 0 140° C. Hot platen: 0 0 0 0.64 0.59 0 160° C.

Also, Adhesive films (F-1) to (F-6) in a B-stage obtained in thepreparations of Samples 5 to 10 were individually laminated using a hotroll laminator under conditions at a temperature of 110° C., a pressureof 0.3 MPa and a speed of 0.3 m/min to prepare adhesive members eachhaving a thickness of 150 μm in a single-layer film form.

By using the obtained adhesive member, a semiconductor chip and a wiringboard using a polyimide film having a thickness of 25 μm as a basematerial were laminated together to prepare a semiconductor devicesample (having solder balls formed on one surface thereof), and the heatresistance, flame retardancy and moisture resistance were examined. Asthe evaluation method for heat resistance, an evaluation of reflow crackresistance and a temperature cycle test were used. The evaluation of thereflow crack resistance was made as follows. A sample was subjected tomoisture absorption under predetermined conditions (85° C./85%/168hours), and placed in an IR reflow furnace in which the temperature wasadjusted so that the maximum temperature of the sample surface became240° C. and this temperature was kept for 20 seconds, and then cooled byallowing the sample to stand at room temperature. The sequence of abovetreatments was repeated three times, and then the resultant sample wasobserved through an ultrasonic microscope in respect of crack andpeeling between the different materials. A sample in which no crack orpeeling was observed was rated “◯”, and a sample in which a crack orpeeling was observed was rated “X”. The evaluation of the temperaturecycle resistance was made as follows. A sample was allowed to stand inan atmosphere at −55° C. for 30 minutes and then stand in an atmosphereat 125° C. for 30 minutes. The sequence of the above treatments wasrepeated 1,000 cycles, and then the resultant sample was observedthrough an ultrasonic microscope in respect of damage such as anoccurrence of peeling or crack. A sample in which no damage was observedwas rated “◯”, and a sample in which a damage was observed was rated“X”. In addition, the evaluation of the moisture resistance was made asfollows. A sample was treated in an atmosphere at a temperature of 121°C. at a humidity of 100% at 2.03×10⁵ Pa (pressure cooker test, PCTtreatment) for 72 hours, and then the resultant sample was observed inrespect of peeling. A sample in which no peeling was recognized in theadhesive member was rated “◯”, and a sample in which peeling wasrecognized in the adhesive member was rated “X”. The results are shownin Table 3.

TABLE 3 Item Sample 5 Sample 6 Sample 7 Sample 8 Sample 9 Sample 10Adhesive film F-1 F-2 F-3 F-4 F-5 F-6 Heat Reflow ◯ ◯ ◯ ◯ ◯ X resistancecrack resistance Temperature ◯ ◯ ◯ ◯ ◯ X cycle resistance Humidity ◯ ◯ ◯◯ ◯ ◯ resistance

As can be clearly seen from the results in Table 2 and Table 3, it canbe understood that an adhesive member which can further suppress thevolatile content during the use can be formed by using a phenolic resinhaving a hydroxyl equivalent of 150 g/eq or more as a curing agent.Also, it can be understood that an adhesive member, a substrate formounting semiconductor, and a semiconductor device each having moreexcellent heat resistance can be provided by using a compound containingan epoxy group as a polymer compound.

Example 3 Sample 11

Cyclohexane was added to a composition comprising 55 parts by weight ofYDCN-703 (manufactured by Tohto Kasei Co., Ltd.; trade name, cresolnovolak type epoxy resin; epoxy equivalent: 210) as an epoxy resin, 45parts by weight of Milex XLC-LL (manufactured by Mitsui Chemicals, Inc.;trade name, phenolic resin; hydroxyl equivalent: 175; water absorption:1.8%; weight loss by heating at 350° C.: 4%) as a phenolic resin, 1.7part by weight of NUC A-189 (manufactured by Nippon Unicar Co., Ltd.;trade name, γ-mercaptopropyltrimethoxysilane) and 3.2 parts by weight ofNUC A-1160 (manufactured by Nippon Unicar Co., Ltd.; trade name,γ-ureidopropyltriethoxysilane) as silane coupling agents, and 32 partsby weight of Aerosil R972 (a filler having an organic group such as amethyl group, on a surface thereof obtained by coating the silicasurface with dimethyldichlorosilane and hydrolyzing the resultant silicain a reactor at 400° C.; manufactured by Nippon Aerosil Co., Ltd.; tradename, silica; average particle diameter: 0.016 μm) as a filler, andmixed by stirring, and further kneaded by means of a beads mill for 90minutes. To the resultant mixture were added 280 parts by weight of anacrylic rubber containing 3% by weight of glycidyl acrylate or glycidylmethacrylate, HTR-860P-3 (manufactured by Teikoku Chemical IndustriesCo., Ltd.; trade name, weight average molecular weight: 800,000) and 0.5part by weight of Curezol 2PZ-CN (manufactured by Shikoku Kasei KogyoCorporation; trade name, 1-cyanoethyl-2-phenylimidazole) as a curingaccelerator, and mixed by stirring, followed by vacuum deaeration. Thevarnish was coated onto a release-treated polyethylene terephthalatefilm having a thickness of 75 μm, and dried by heating at 140° C. for 5minutes to form a coating film in a B-stage having a thickness of 75 μm,thus preparing an adhesive film equipped with a support film.

Sample 12

Completely the same procedure as in the preparation of Sample 11 wasconducted except that, instead of 55 parts by weight of YDCN-703, 51parts by weight of EPON 1031S (trade name, manufactured by Japan EpoxyResins Co., Ltd.; polyfunctional epoxy resin; epoxy equivalent: 200) wasused to prepare an adhesive film.

Sample 13

Completely the same procedure as in the preparation of Sample 11 wasconducted except that, instead of 45 parts by weight of Milex XLC-LL, 43parts by weight of Milex XLC-4L (manufactured by Mitsui Chemicals, Inc.;trade name, phenolic resin; hydroxyl equivalent: 169; water absorption:1.6%; weight loss by heating at 350° C.: 4%) was used to prepare anadhesive film.

Sample 14

Completely the same procedure as in the preparation of Sample 11 wasconducted except that, instead of 45 parts by weight of Milex XLC-LL, 37parts by weight of Plyofen LF2882 (manufactured by Dainippon Ink &Chemicals, Inc.; trade name, bisphenol A novolak rein; hydroxylequivalent: 118; water absorption: 4.4%; weight loss by heating at 350°C.: 18%) was used to prepare an adhesive film.

Comparative Sample 1

Completely the same procedure as in the preparation of Sample 11 wasconducted except that a bisphenol A type bifunctional epoxy resin(YD8125, manufactured by Tohto Kasei Co., Ltd.) was used as an epoxyresin to prepare an adhesive film. Incidentally, the mixture varnishcomprising the epoxy resin and the rubber was cast onto a protectingfilm and dried at 90° C. for 30 minutes to prepare a film (50 μm inthickness). Transmittance of a visible light (600 nm) of the film was60%, and it was compatible.

With respect to the obtained adhesive films, the tests mentioned belowwere conducted. The results are shown in Table 4.

(Measurement Method for Peel Strength)

50 μm polyimide films were laminated on both surfaces of the adhesivefilm by means of a hot roll laminator (80° C., 0.3 m/min, 0.3 MPa), andcured at 170° C. for one hour. The laminated cured product was cut into10 mm width to prepare a sample for evaluation. By using Tensilon, ModelUTM-4-100, manufactured by TOYO BALWIN, a value when the sample wassubjected to peeling at an angle of 180° at a tensile speed of 50 mm/minwas measured. The value was a simple average value of three samples.

(Measurement Method for Elastic Modulus)

An adhesive film having an initial length (L) was prepared, and placedin a thermostatic chamber at 240° C. in a state that a constant load (W)was applied thereto. An amount of elongation (ΔL) and a cross-sectionalarea (S) of the adhesive film after placing in the chamber weredetermined and an elastic modulus in tensile (E′) was calculated fromthe following formula:

E′=L·W/(ΔL·S).

(Reflow Resistance Test)

A semiconductor chip and a wiring board using a polyimide film having athickness of 25 μm as a base material were laminated onto the adhesivefilm and cured to prepare a semiconductor device sample. In accordancewith JEDEC standard J-STD-020A, the prepared semiconductor device samplewas passed three times through an IR reflow furnace in which thetemperature was adjusted so that the maximum temperature of the samplesurface became 245° C., 260° C. or 265° C. The resultant sample wasobserved by visual examination and through an ultrasonic microscope inrespect of peeling. A sample in which peeling with a diameter of 1 mm ormore was not observed was rated “◯”, and a sample in which such peelingwas observed was rated “X”.

(Soldering Heat Resistance Test)

Polyimide films each having a thickness of 50 μm were laminated on bothsurfaces of the obtained adhesive film using a hot roll laminator underconditions at a temperature of 80° C., a pressure of 0.3 MPa and a speedof 0.3 m/min, and then cured at 170° C. for one hour. Several specimensof 30 mm×30 mm were prepared from the resultant sample, and examinedwith respect to the heat resistance. The evaluation method for the heatresistance was conducted by a test for resistance to soldering heatafter absorbing moisture as follows. A sample was allowed to stand for48 hours in an environment at 85° C. at a relative humidity of 85%, andthen placed in a solder bath at 240° C. to 280° C. The resultant samplewas examined whether or not an unfavorable phenomenon such asblistering, occurred until 120 seconds. An adhesive film for which anunfavorable phenomenon was observed in all the samples was rated “X”, anadhesive film for which an unfavorable phenomenon was observed in asample and unfavorable phenomenon was not observed in another was rated“Δ”, and an adhesive film for which unfavorable phenomenon was notobserved in any of the samples was rated “◯”.

(PCT Resistance Test)

The evaluation for the PCT resistance was carried out by observing thepresence or absence of peeling of the adhesive member after placing itin an atmosphere at a temperature of 121° C., a humidity of 100% and at2 atm. (pressure cooker test; PCT treatment) for 168 hours.

(Analysis of Islands-in-Sea Structure)

For determining the ratio of the volume VA of the filler contained inthe epoxy resin phase to the volume VB of the filler contained in therubber component phase after being cured, the cross-section of the filmwas observed through a scanning type electron microscope, and, withrespect to each of the regions comprised mainly of A and B,respectively, a peak of the atoms which constitute the filler ismeasured by means of an XMA. From the height ratio between these peaks,VA/VB is determined.

Also, the islands-in-sea structure was observed by investigating thecross-section of the cured product through a scanning type electronmicroscope to measure a value of the relationship (S/V^(1/2)) betweenthe length S of the outer periphery of the islands phase and thecross-sectional area V.

TABLE 4 Sample Sample Sample Sample Comparative Evaluation 11 12 13 14Sample 1 Peel 240° C. 108 74 110 42 11 strength (N/m) Elastic 240° C.2.9 3.6 2.8 2.4 3.8 modulus (MPa) Soldering 240° C. ◯ ◯ ◯ ◯ X heat 260°C. ◯ ◯ ◯ Δ X resistance 280° C. ◯ Δ ◯ Δ X PCT resistance ◯ ◯ ◯ X XCompatibility Incompatible Incompatible Incompatible IncompatibleCompatible VA/VB 1.1 1.0 1.1 1.1 1.1 S/V^(1/2) 3.7 3.8 3.8 3.8 3.7Softening point of 80 90 80 80 20 to 40 Epoxy resin (° C.) Waterabsorption of 1.8 1.8 1.6 4.4 1.8 Phenolic resin (%) Weight loss 4 4 418 4 (350° C.) % Reflow 245° C. ◯ ◯ ◯ ◯ X resistance 260° C. ◯ ◯ ◯ X X265° C. ◯ ◯ ◯ X X

As can be seen from Table 4, the adhesive films in Samples 11 to 13 eachprepared by using the phenolic resin of formula (I) of the presentinvention have especially excellent peel strength, as compared to thefilm in Comparative sample 1, and it can be clearly understood that thatthe semiconductor devices prepared by using these adhesive films aregood in both of resistance to soldering heat after absorbing moistureand PCT resistance.

Example 4 Sample 15

Methyl ethyl ketone was added to a composition comprising 45 parts byweight of a bisphenol A type epoxy resin (epoxy equivalent: 190, EPIKOTE828, manufactured by Japan Epoxy Resins Co., Ltd. was used) and 15 partsby weight of a cresol novolak type epoxy resin (epoxy equivalent: 195,ESCN195, manufactured by Sumitomo Chemical Co., Ltd. was used) as epoxyresins, 40 parts by weight of a phenolic novolak resin (Plyofen LF2882,manufactured by Dainippon Ink & Chemicals, Inc. was used) as a curingagent for the epoxy resins, 0.7 part by weight ofγ-glycidoxypropyltrimethoxysilane (NUC A-187 manufactured by NipponUnicar Co., Ltd. was used) as a silane coupling agent, and 10 parts byweight of silica filler (NanoTek SiO₂ manufactured by C.I. KASEI CO.,LTD. was used; contact angle with water: 43 degrees; average particlediameter: 0.012 μm), and mixed by stirring, and further kneaded by meansof a beads mill for 90 minutes. To the resultant mixture were added 150parts by weight of an acrylic rubber containing 2 to 6% by weight ofglycidyl acrylate or glycidyl methacrylate and having a weight averagemolecular weight of 100,000 or more (molecular weight: 1,000,000,HTR-860P-3 manufactured by Teikoku Chemical Industries Co., Ltd. wasused) and 0.5 part by weight of 1-cyanoethyl-2-phenylimidazole (Curezol2PZ-CN, manufactured by Shikoku Kasei Kogyo Corporation was used) as acuring accelerator, and mixed by means of a stirring motor for 30minutes to obtain a varnish. The varnish was coated onto arelease-treated polyethylene terephthalate film having a thickness of 75μm, and dried by heating to 140° C. for 5 minutes to form a coating filmin a B-stage having a thickness of 75 μm, thus preparing an adhesivefilm equipped with a support film.

Sample 16

Methyl ethyl ketone was added to a composition comprising 60 parts byweight of a cresol novolak type epoxy resin (epoxy equivalent: 210,YDCN-703 manufactured by Tohto Kasei Co., Ltd. was used) as an epoxyresin, 40 parts by weight of a phenolic novolak resin (Plyofen LF2882manufactured by Dainippon Ink & Chemicals, Inc. was used) as a curingagent for the epoxy resin, 200 parts by weight of an acrylic rubbercontaining 2 to 6% by weight of glycidyl acrylate or glycidylmethacrylate (weight average molecular weight: 1,000,000, HTR-860P-3manufactured by Teikoku Chemical Industries Co., Ltd. was used), 0.5part by weight of 1-cyanoethyl-2-phenylimidazole (Curezol 2PZ-CN wasused) as a curing accelerator, 0.7 part by weight ofγ-ureidopropyltriethoxysilane (NUC A-1160 manufactured by Nippon UnicarCo., Ltd. was used) as a silane coupling agent, and 10 parts by weightof silica filler (NanoTek SiO₂ manufactured by C.I. KASEI CO., LTD. wasused; contact angle with water: 43 degrees; average particle diameter:0.012 μm), and mixed by stirring, and further kneaded by means of abeads mill, followed by vacuum deaeration. The varnish was coated onto arelease-treated polyethylene terephthalate film having a thickness of 75μm, and dried by heating to 140° C. for 5 minutes to form a coating filmin a B-stage having a thickness of 75 μm, thus preparing an adhesivefilm equipped with a support film.

Sample 17

Substantially the same procedure as in the preparation of Sample 15 wasconducted except that 15 parts by weight of silica (Aerosil 50manufactured by Nippon Aerosil Co., Ltd.; contact angle: 95 degrees;average particle diameter: 0.03 μm) was used as a filler to prepare anadhesive film.

Sample 18

Substantially the same procedure as in the preparation of Sample 15 wasconducted except that 15 parts by weight of diantimony trioxide (PATOX-Umanufactured by Nihon Mining & Concentrating Co., Ltd.; contact anglewith water: 43 degrees; average particle diameter: 0.02 μm) was used asa filler to prepare an adhesive film.

When the sample was observed through a scanning type electron microscopewith respect to VA/VB in the same manner as in Example 3, it was 2.5.

Sample 19

Substantially the same procedure as in the preparation of Sample 15 wasconducted except that 15 parts by weight of diantimony trioxide(PATOX-HS manufactured by Nihon Mining & Concentrating Co., Ltd.;contact angle with water: 43 degrees; average particle diameter: 5 μm)was used as a filler to prepare an adhesive film.

When the sample was observed through a scanning type electron microscopewith respect to S/V^(1/2) in the same manner as in Example 3, it was4.0.

Sample 20

Substantially the same procedure as in the preparation of sample 15 wasconducted except that silica filler, Aerosil R972, manufactured byNippon Aerosil Co., Ltd. (a filler having an organic group such as amethyl group, on a surface thereof obtained by coating the silicasurface with dimethyldichlorosilane and hydrolyzing the resultant silicain a reactor at 400° C.; contact angle with water: 160 degrees; averageparticle diameter: 0.02 μm) was used as a filler to prepare an adhesivefilm.

Polyimide films each having a thickness of 50 μm were laminated on bothsurfaces of the obtained adhesive film using a hot roll laminator underconditions at a temperature of 80° C., a pressure of 0.3 MPa and a speedof 0.3 m/min, and then cured at 170° C. for one hour. The resultantsample was examined with respect to the heat resistance. The evaluationmethod for the heat resistance was conducted by a test for resistance tosoldering heat after absorbing moisture as follows. A sample was allowedto stand for 48 hours in an environment at a temperature of 85° C., arelative humidity of 85%, and then placed in a solder bath at 240° C. Asample in which blistering was observed less than 40 seconds was rated“X”, a sample in which blistering was observed 40 seconds or more toless than 120 seconds was rated “◯”, and a sample in which no blisteringwas observed in 120 seconds or more was rated “⊚”.

The evaluation for the moisture resistance was made as follows. A samplewas placed in an atmosphere at a temperature of 121° C., a humidity of100% and at 2 atm. (pressure cooker test; PCT treatment), and then,observed every 100 hours in respect of peeling of the adhesive member. Asample in which no peeling was observed in the adhesive member was rated“◯”, and a sample in which peeling was observed in the adhesive memberwas rated “X”. The results are shown in Table

TABLE 5 Sample Sample Sample Sample Sample Sample 15 16 17 18 19 20Compatibility Incompatible Incompatible Incompatible IncompatibleIncompatible Incompatible Soldering heat ⊚ ⊚ ⊚ ⊚ ⊚ ◯ resistance aftermoisture absorption PCT 100 hr ◯ ◯ ◯ ◯ ◯ ◯ PCT 200 hr ◯ ◯ ◯ ◯ ◯ ◯ PCT300 hr ◯ ◯ ◯ ◯ ◯ ◯ PCT 400 hr ◯ ◯ ◯ X X X

Samples 15 to 19 are adhesive films using an inorganic filler having acontact angle with water of 100 degrees or less, and the semiconductordevice produced by using these adhesive films were good both inresistance to soldering heat after absorbing moisture and PCTresistance. Sample 18 using a filler having an average particle diameterof 0.02 μm has good PCT resistance as compared to Sample 19 using afiller having an average particle diameter of 5 μm. Sample 20 is asample in which a filler having a large contact angle with water wasused.

Example 5 Sample 21

Methyl ethyl ketone was added to a resin comprising 45 parts by weightof a bisphenol A type epoxy resin (epoxy equivalent: 190, EPIKOTE 828manufactured by Japan Epoxy Resins Co., Ltd. was used) and 151 parts byweight of a cresol novolak type epoxy resin (epoxy equivalent: 195,ESCN195 manufactured by Sumitomo Chemical Co., Ltd. was used) as epoxyresins, and 40 parts by weight of a phenolic novolak resin (PlyofenLF2882 manufactured by Dainippon Ink & Chemicals, Inc. was used) as acuring agent for the epoxy resins, was added 10 parts by weight ofantimony oxide filler having an average particle diameter of 0.02 μm(PATOX-U manufactured by Nihon Mining & Concentrating Co., Ltd. wasused), and then, 0.7 part by weight of γ-glycidoxypropyltrimethoxysilane(NUC A-187 manufactured by Nippon Unicar Co., Ltd. was used) as a silanecoupling agent, and mixed by stirring, and further kneaded by means of abeads mill for 90 minutes. To the resultant mixture were added 150 partsby weight of an acrylic rubber containing 2 to 6% by weight of glycidylacrylate or glycidyl methacrylate and having a weight average molecularweight of 100,000 or more (molecular weight: 1,000,000, HTR-860P-3manufactured by Teikoku Chemical Industries Co., Ltd. was used) and 0.5part by weight of 1-cyanoethyl-2-phenylimidazole (Curezol 2PZ-CNmanufactured by Shikoku Kasei Kogyo Corporation was used) as a curingaccelerator, and mixed by means of a stirring motor for 30 minutes toobtain a varnish. The varnish was coated onto a release-treatedpolyethylene terephthalate film having a thickness of 75 μm, and driedby heating at 140° C. for 5 minutes to form a coating film in a B-stagehaving a thickness of 75 μm, thus preparing an adhesive film equippedwith a support film. The cross-section of the prepared film was observedthrough a scanning type electron microscope. As a result, islandscomprised of the epoxy resin having a diameter of 1 μm and a seacomprised of the rubber were observed. The ratio (VA/VB) of the amountVA of antimony atoms in the islands portion to the amount VB of antimonyatoms in the sea portion was analyzed by means of an XMA, and it wasfound to be 3. Also, when S/V^(1/2) of the sample was observed through ascanning type electron microscope in the same manner as in Example 3, itwas 4.1.

Sample 22

Substantially the same procedure as in the preparation of sample 21 wasconducted except that the epoxy resin and the rubber were firstly mixedtogether and then the filler was added thereto to prepare a film. Froman analysis by means of an XMA, it was found that VA/VB is 1.1. Also,when S/V^(1/2) of the sample was observed through a scanning typeelectron microscope in the same manner as in Example 3, it was 4.0.

Polyimide films each having a thickness of 50 μm were laminated on bothsurfaces of each of the adhesive films in Samples 21 and 22 using a hotroll laminator under conditions at a temperature of 80° C., a pressureof 0.3 MPa and a speed of 0.3 m/min, and then cured at 170° C. for onehour. The resultant sample was examined with respect to the heatresistance and PCT resistance. The evaluation method for the heatresistance was conducted by a test for resistance to soldering heatafter absorbing moisture as follows. A sample was allowed to stand for48 hours in an environment at 85° C./a relative humidity of 85%, andthen placed in a solder bath at 240° C. A sample in which blistering wasobserved less than 40 seconds was rated “X”, a sample in whichblistering was observed 40 seconds or more to less than 120 seconds wasrated “◯”, and a sample in which no blistering was observed in 120seconds or more was rated “⊚”. In addition, the evaluation for themoisture resistance was made as follows. A sample was placed in anatmosphere at a temperature of 121° C., a humidity of 100% and at 2 atm.(pressure cooker test; PCT treatment), and then, observed every 100hours in respect of peeling of the adhesive member. A sample in which nopeeling was observed in the adhesive member was rated “◯”, and a samplein which peeling was observed in the adhesive member was rated “X”. Theresults are shown in Table 6.

TABLE 6 Sample 21 Sample 22 Compatibility Incompatible IncompatibleSoldering heat ⊚ ◯ resistance after moisture absorption PCT 100 hr ◯ ◯PCT 200 hr ◯ ◯ PCT 300 hr ◯ X PCT 400 hr X X

From the above, it can be understood that, by preliminarily mixing theepoxy resin with the filler, a larger amount of the filler can beincorporated into the epoxy resin phase, whereby making it possible toimprove the heat resistance and moisture resistance as well asreliability.

Example 6 Sample 23

Methyl ethyl ketone was added to a composition comprising 17.2 g of abisphenol A type epoxy resin (epoxy equivalent: 190, EPIKOTE 828manufactured by Yuka Shell Epoxy Co., Ltd. was used) and 5.8 g of acresol novolak type epoxy resin (epoxy equivalent: 195, ESCN195manufactured by Sumitomo Chemical Co., Ltd. was used) as epoxy resins,15.3 g of a phenolic novolak resin (Plyofen LF2882 manufactured byDainippon Ink & Chemicals, Inc. was used) as a curing agent for theepoxy resins, 0.2 g of γ-glycidoxypropyltrimethoxysilane (NUC A-187manufactured by Nippon Unicar Co., Ltd. was used) as a silane couplingagent, and 3.8 g of silica filler (NanoTek SiO₂ (average particlediameter: 0.012 μm) manufactured by C.I. KASEI CO., LTD. was used), andmixed by stirring, and further kneaded by means of a beads mill for 90minutes.

To the resultant mixture were added 57.5 g of an epoxy-containingacrylic rubber (weight average molecular weight: about 700,000,HTR-860P-3 manufactured by Teikoku Chemical Industries Co., Ltd. wasused) and 0.2 g of 1-cyanoethyl-2-phenylimidazole (Curezol 2PZ-CNmanufactured by Shikoku Corporation was used) as a curing accelerator,and mixed by means of a stirring motor for 30 minutes. The resultantvarnish was coated onto a release-treated polyethylene terephthalatefilm having a thickness of 75 μm, and dried by heating at 140° C. for 5minutes to form a coating film in a B-stage having a thickness of 75 μm,thus preparing an adhesive film equipped with a support film.

The weight average molecular weight was measured by a GPC method usingthe following apparatus and columns and using a calibration curveobtained by standard polystyrene.

(GPC Measurement)

Apparatus: Model HPLC635 manufactured by Hitachi, Ltd.Columns: Gel pack R-440, R-450 and R-400M manufactured by HitachiChemical Co., Ltd.

Sample 24

Methyl ethyl ketone was added to a composition comprising 19.3 g of acresol novolak type epoxy resin (epoxy equivalent: 210, YDCN-703manufactured by Tohto Kasei Co., Ltd. was used) as an epoxy resin, 12.9g of a cresol novolak resin (Plyofen LF2882 manufactured by DainipponInk & Chemicals, Inc. was used) as a curing agent for the epoxy resin,64.3 g of an epoxy-containing acrylic rubber (weight average molecularweight: about 700,000, HTR-860P-3 manufactured by Teikoku ChemicalIndustries Co., Ltd. was used) as an epoxy group-containing acryliccopolymer, 0.2 g of 1-cyanoethyl-2-phenylimidazole (Curezol 2PZ-CNmanufactured by Shikoku Corporation was used) as a curing accelerator,0.3 g of γ-ureidopropyltriethoxysilane (NUC A-1160 manufactured byNippon Unicar Co., Ltd. was used) as a silane coupling agent, and 3.0 gof silica filler (NanoTek SiO₂ (average particle diameter: 0.012 μm)manufactured by C.I. KASEI CO., LTD. was used), and mixed by stirring,and further kneaded by means of a beads mill for 90 minutes.

The varnish was coated onto a release-treated polyethylene terephthalatefilm having a thickness of 75 μm, and dried by heating at 140° C. for 5minutes to form a coating film in a B-stage having a thickness of 75 μm,thus preparing an adhesive film having a support film. The weightaverage molecular weight was measured in the same manner as in thepreparation of Sample 23.

Sample 25

Substantially the same procedure as in the preparation of sample 23 wasconducted except that 3.8 g of silica (Aerosil 50 (average particlediameter is 0.03 μm) manufactured by Nippon Aerosil Co., Ltd.) was usedas a filler to prepare an adhesive film.

Sample 26

Substantially the same procedure as in the preparation of Sample 23 wasconducted except that 3.8 g of diantimony trioxide (PATOX-U (averageparticle diameter is 0.02 μm) manufactured by Nihon Mining &Concentrating Co., Ltd.) was used as a filler to prepare an adhesivefilm.

Comparative Sample 2

Substantially the same procedure as in the preparation of Sample 23 wasconducted except that 0.05 g of diantimony trioxide (PATOXU (averageparticle diameter is 0.02 μm) manufactured by Nihon Mining &Concentrating Co., Ltd.) was used as a filler to prepare an adhesivefilm.

With respect to each of the adhesive films obtained under differentconditions, a volume percentage of the pores in the film was determinedby making calculation in accordance with the following method.

(1) In a view through a SEM, S-4500, manufactured by Hitachi Ltd., asquare region, having a side with a length of 100 times the averageparticle diameter of the filler used and which has 50 pores, is selectedto take a SEM photograph.(2) The area of the square region and the total area of the 50 pores aredetermined as follows. A transparent film having a uniform density andan even thickness is placed on the SEM photograph, and all the 50 poresare traced by a pen and the traced portions are cut out.(3) The predetermined area portion (including the 50 pores portions) istraced by a pen in the same manner as in item (2) above, and the tracedportion is cut out.(4) The weight of each of the cut out portions obtained in items (2) and(3) above is measured to determine a (2)/(3) value.(5) V=[(2)/(3)]^(3/2) is determined.(6) The sequence of the operations of items (1) to (5) above is repeatedfive times, and an average of V values obtained is taken as a volumepercentage, and the results are shown in Table 7.

Further, polyimide films each having a thickness of 50 μm were laminatedon both surfaces of each of the adhesive films using a hot rolllaminator under conditions at a temperature of 80° C., a pressure of 0.3MPa and a conveying speed of 0.3 m/min, and then cured at 170° C. forone hour. The resultant samples were individually examined with respectto the heat resistance and PCT resistance (pressure cooker test).

The evaluation method for heat resistance was conducted by a test forresistance to soldering heat after absorbing moisture as follows. Asample was allowed to stand for 48 hours in an environment at 85° C./arelative humidity of 85%, and then placed in a solder bath at 240° C. Asample in which blistering was observed less than 40 seconds was rated“X”, a sample in which blistering was observed 40 seconds or more toless than 120 seconds was rated “◯”, and a sample in which no blisteringwas observed in 120 seconds or more was rated “⊚”.

The evaluation for the PCT resistance was made as follows. A sample wastreated in an atmosphere at 121° C., 2 atm. and a humidity of 100% for apredetermined time, and then, observed in respect of appearance. Asample in which an unfavorable phenomenon such as blistering, was notobserved was rated “◯”, and a sample in which an unfavorable phenomenonwas observed was rated “X”.

The contact angle a of filler with water was measured as follows. Afiller was subjected to compression molding to prepare a plane plate,and a water drop was placed on the plate and the angle of the water dropto the plate was measured by means of a contact angle meter. Thismeasurement was repeated 10 times to obtain an average value, and thisvalue was used as a value of the contact angle. The contact angle b withwater of the material obtained by applying the composition and dryingthe composition applied was measured in the same manner as in contactangle a.

TABLE 7 Comparative Sample 23 Sample 24 Sample 25 Sample 26 Sample 2Compatibility Incompatible Incompatible Incompatible IncompatibleIncompatible Contact angle of filler 43.2 43.2 96.5 41.7 128.0 withwater (° C.): a Contact angle of resin 144.0 128.0 144.0 144.0 144.0with water (° C.): b Ratio of 0.30 0.33 0.67 0.29 0.88 Contact angle(a/b) Existence of pores of Present Present Present Present Present 0.1to 2.0 μm Volume content of 2.8 1.9 2.4 3.6 0.01 pores (vol %) Solderingheat ⊚ ⊚ ◯ ◯ X resistance after moisture absorption PCT 100 hr ◯ ◯ ◯ ◯ ◯PCT 200 hr ◯ ◯ ◯ ◯ X PCT 300 hr ◯ ◯ ◯ ◯ X PCT 400 hr ◯ ◯ ◯ ◯ X PCT 500hr ◯ ◯ X X X

Samples 23 to 26 are adhesive films in which 0.01 to 2.0 μm pores werepresent therein in the range of 0.1 to 20% by volume, and the laminatesfor semiconductor produced by using these adhesive films had excellentresistance to soldering heat after absorbing moisture and had a PCTresistance of 300 to 400 hours.

Further, Sample 24 employs silica as filer and does not employ abisphenol A type epoxy resin having a mutagen. Therefore, the sample isadvantageous not only in that it is easy to handle but also in that ithas excellent resistance to soldering heat after absorbing moisture andgood PCT resistance as much as Sample 23, while maintainingcharacteristics of having less adverse effect on the environment andhuman body.

Comparative sample 2 has pores outside the range of 0.1 to 20% byvolume, and is insufficient in resistance to soldering heat afterabsorbing moisture and has a PCT resistance of 100 hours, which is farshorter than those of Samples 23 to 26.

Also, Samples 23 to 26 are adhesive films having a contact angle ratio(a/b) of less than ¾, i.e., less than 0.75, and the semiconductordevices prepared by using these adhesive films had excellent resistanceto soldering heat after absorbing moisture and a PCT resistance as goodas 400 hours or more.

Comparative sample 2 has a contact angle ratio of 0.75 or more, and isinsufficient in resistance to soldering heat after absorbing moistureand a PCT resistance of 100 hours, which is far shorter than those ofSamples 23 to 26.

INDUSTRIAL APPLICABILITY

By virtue of having the above-mentioned construction, the adhesivecomposition of the present invention has excellent moisture resistance,reflow crack resistance and heat resistance. Also, by further adding aninorganic filler, there can be obtained an adhesive composition which isadvantageous in that it is improved both in elastic modulus at hightemperatures and peel strength at high temperatures to exhibit an effectof preventing reflow crack and thus excellent in reflow crackresistance. Further, by using the adhesive composition of the presentinvention, an adhesive film excellent in heat resistance and PCTresistance can be produced. The adhesive film of the present inventionis excellent in heat resistance after absorbing moisture, reflowresistance, adhesion properties after absorbing moisture, etc.

Also, the adhesive film and the wiring board for mounting semiconductoreach produced from the adhesive composition of the present invention,and the semiconductor device produced by using the same have excellentheat resistance and PCT resistance. According to the present invention,there can be provided an adhesive composition from which an adhesivemember can be formed wherein the adhesive member is advantageous notonly in that the adhesive member has heat resistance and moistureresistance necessary for mounting a semiconductor device on a substratefor mounting semiconductor even when the difference in coefficient ofthermal expansion between the semiconductor device and the substrate islarge, but also in that the adhesive member can suppress volatilizationof the volatile components when being used, an adhesive member, asubstrate for mounting semiconductor, and a semiconductor device whichuse the adhesive composition.

1. An adhesive film comprising an adhesive composition which comprises:(a) an epoxy resin; (b) a curing agent which mainly comprises a phenolicresin having a hydroxyl equivalent of 150 g/eq or more; and (c) apolymer compound incompatible with said epoxy resin, wherein a ratio ofA/B is 0.24:1 to 1:1, where A represents a total weight of (a) the epoxyresin and (b) the curing agent and B represents a weight of (c) thepolymer compound incompatible with the epoxy resin, and the adhesivecomposition has been formed into a film, wherein the components of theadhesive composition are separated into two phases after being cured asviewed in the cross-section thereof, and wherein (b) the curing agent isa phenolic resin represented by the following general formula (I):

wherein R¹ each may be the same or different from each other andrepresents a hydrogen atom, a straight or branched alkyl group having 1to 10 carbon atoms, a cyclic alkyl group, an aralkyl group, an alkenylgroup, a hydroxyl group, an aryl group, or a halogen atom; n representsan integer of 1 to 3; and m represents an integer of 0 to 50, andwherein (b) the curing agent exhibits a weight loss by heating at 350°C. (temperature elevation rate: 5° C./min.; atmosphere:nitrogen gas) ofless than 5% by weight as measured by a thermo-gravimetric analyzer(TGA).
 2. The adhesive film according to claim 1, wherein (a) the epoxyresin is a solid epoxy resin having a softening point of 50° C. or moreas measured by a ring and ball method.
 3. The adhesive film according toclaim 1, wherein (a) the epoxy resin has no mutagen.
 4. The adhesivefilm according to claim 1, wherein the phenolic resin represented bygeneral formula (I) has a water absorption of 2% by volume or less. 5.The adhesive film according to claim 1, wherein (c) the polymer compoundincompatible with the epoxy resin is a functional group-containingacrylic copolymer.
 6. The adhesive film according to claim 5, whereinthe functional group-containing acrylic copolymer is an epoxygroup-containing acrylic copolymer.
 7. The adhesive film according toclaim 6, wherein the epoxy group-containing acrylic copolymer contains0.5 to 6% by weight of glycidyl acrylate or glycidyl methacrylate as astarting material therefor.
 8. The adhesive film according to claim 5,wherein the functional group-containing acrylic copolymer has a weightaverage molecular weight of 100,000 or more.
 9. The adhesive filmaccording to claim 5, wherein the functional group-containing acryliccopolymer has a glass transition temperature of −50° C. to 30° C. 10.The adhesive film according to claim 1, which further comprises (e) acuring accelerator.
 11. The adhesive film according to claim 10, wherein(e) the curing accelerator is an imidazole compound.
 12. The adhesivefilm according to claim 1, wherein the two phases comprise a sea phaseand an islands phase, and wherein, a length of an outer periphery of theislands phase represented by S and an area of a cross-sectionrepresented by V satisfy a relationship represented by the followingformula (1):S/√V>3.6  (1).
 13. The adhesive film according to claim 1, whichsatisfies at least one of the following requirements (i) and (ii): (i)the adhesive composition gives a cured product having a storage elasticmodulus at 240° C. of 1 to 20 MPa; and (ii) the adhesive composition haspores having an average diameter of 0.01 μm to 2 μm after being curedand a volume percentage of the pores after being cured is 0.1 to 20% byvolume.
 14. The adhesive film according to claim 1, which exhibitslowering in flow after 72 hours at 60° C. of 50% or less.
 15. Theadhesive film according to claim 1, wherein (a) the epoxy resin is abisphenol A epoxy resin, (b) the curing agent is a zylok phenolic resin,and (c) the polymer compound incompatible with the epoxy resin is anepoxy group-containing acrylic rubber.
 16. The adhesive film accordingto claim 1, wherein said adhesive composition gives a cured producthaving a storage elastic modulus at 240° C. of 1 to 20 MPa.
 17. Theadhesive film according to claim 16, having pores with an averagediameter of 0.01 μm to 2 μm after being cured, and a volume percentageof the pores in the composition after being cured is 0.1 to 20% byvolume.
 18. The adhesive film according to claim 1, having pores with anaverage diameter of 0.01 μm to 2 μm after being cured, and a volumepercentage of the pores in the composition after being cured is 0.1 to20% by volume.
 19. The adhesive film according to claim 1, whereinvisible light transmittance of a film 50 μm thick of said epoxy resinand polymer compound, having a component ratio of 1:1, prepared from avarnish of said epoxy resin and said polymer compound, is less than 30%.20. The adhesive film according to claim 1, wherein amount of epoxyresin in the adhesive film is less than amount of said polymer compoundin said film.
 21. An adhesive film comprising an adhesive compositionwhich comprises: (a) an epoxy resin; (b) a curing agent which mainlycomprises a phenolic resin having a hydroxyl equivalent of 150 g/eq ormore; and (c) a polymer compound incompatible with said epoxy resin,wherein a ratio of A/B is 0.24:1 to 1:1, where A represents a totalweight of (a) the epoxy resin and (b) the curing agent and B representsa weight of (c) the polymer compound incompatible with the epoxy resin,and the adhesive composition has been formed into a film, wherein theadhesive film gives a cured product having a storage elastic modulus at240° C. of 1 to 20 MPa, wherein (b) the curing agent is a phenolic resinrepresented by the following general formula (I):

wherein R¹ each may be the same or different from each other andrepresents a hydrogen atom, a straight or branched alkyl group having 1to 10 carbon atoms, a cyclic alkyl group, an aralkyl group, an alkenylgroup, a hydroxyl group, an aryl group, or a halogen atom; n representsan integer of 1 to 3; and m represents an integer of 0 to 50, wherein(b) the curing agent exhibits a weight loss by heating at 350° C.(temperature elevation rate: 5° C./min.; atmosphere:nitrogen gas) ofless than 5% by weight as measured by a thermo-gravimetric analyzer(TGA).
 22. An adhesive film comprising an adhesive composition whichcomprises: (a) an epoxy resin; (b) a curing agent which mainly comprisesa phenolic resin having a hydroxyl equivalent of 150 g/eq or more; and(c) a polymer compound incompatible with said epoxy resin, wherein aratio of A/B is 0.24:1 to 1:1, where A represents a total weight of (a)the epoxy resin and (b) the curing agent and B represents a weight of(c) the polymer compound incompatible with the epoxy resin, and theadhesive composition has been formed into a film, wherein said adhesivefilm has pores with an average diameter of 0.01 μm to 2 μm after beingcured, and a volume percentage of the pores in the composition afterbeing cured is 0.1 to 20% by volume, wherein (b) the curing agent is aphenolic resin represented by the following general formula (I):

wherein R¹ each may be the same or different from each other andrepresents a hydrogen atom, a straight or branched alkyl group having 1to 10 carbon atoms, a cyclic alkyl group, an aralkyl group, an alkenylgroup, a hydroxyl group, an aryl group, or a halogen atom; n representsan integer of 1 to 3; and m represents an integer of 0 to 50, wherein(b) the curing agent exhibits a weight loss by heating at 350° C.(temperature elevation rate: 5° C./min.; atmosphere:nitrogen gas) ofless than 5% by weight as measured by a thermo-gravimetric analyzer(TGA).
 23. The adhesive film according to claim 21, wherein (a) theepoxy resin is a bisphenol A epoxy resin, (b) the curing agent is azylok phenolic resin, and (c) the polymer compound incompatible with theepoxy resin is an epoxy group-containing acrylic rubber.
 24. Theadhesive film according to claim 22, wherein (a) the epoxy resin is abisphenol A epoxy resin, (b) the curing agent is a zylok phenolic resin,and (c) the polymer compound incompatible with the epoxy resin is anepoxy group-containing acrylic rubber.
 25. The adhesive film accordingto claim 1, wherein equivalents ratio of epoxy equivalent to hydroxylequivalent of the epoxy resin and phenolic resin is in the range of0.70:0.30 to 0.30:0.70.
 26. The adhesive film according to claim 1,wherein the curing agent is included in an amount of 0.01 to 5.0equivalents based on 1 mol of the epoxy group.
 27. The adhesive filmaccording to claim 1, wherein the adhesive composition exhibits a weightloss on heating at 270° C. of 2% by weight or less.
 28. The adhesivefilm according to claim 1, wherein the adhesive film has the propertythat it can be laminated as a film on a substrate, for acting as anadhesive.
 29. The adhesive film according to claim 28, wherein saidsubstrate is a semiconductor chip.